FUNDAMENTALS OF NETWORKING

Q1 – Cloud Storage

In a cloud-based application where scalability is crucial, which cloud storage option allows dynamic scaling without manual intervention?

Options:
 A. Block Storage
B. File Storage
C. ✅ Object Storage
D. Tape Storage=

✅ Correct Answer: C. Object Storage

Explanation of All Options:

• A. Block Storage: Data stored in fixed-size blocks. High performance, but manual scaling — used for databases & VMs.
• B. File Storage: Uses folder/file hierarchy. Easy sharing but limited scaling — best for shared drives.
• ✅ C. Object Storage: Stores data as objects with metadata. Auto-scales dynamically across servers — perfect for cloud apps.
• D. Tape Storage: Sequential offline storage, used only for archiving — no real-time scaling.

💡 Quick Tip:

“Auto scaling = Object Storage”
Block = performance, File = sharing, Object = scalability, Tape = backup.

Q2: Which protocol is commonly used to secure data in transit over the internet?

Options:
 (a) HTTP
(b) FTP
(c) ✅ SSL/TLS
(d) SMTP

✅ Correct Answer: (c) SSL/TLS

Explanation:
 SSL (Secure Sockets Layer) and TLS (Transport Layer Security) are cryptographic protocols used to encrypt data during transmission between client and server, ensuring confidentiality, integrity, and authentication.
When SSL/TLS is applied to HTTP, it becomes HTTPS, which secures websites.

Other Options:
 (a) HTTP: Transfers data in plain text — not secure.
(b) FTP: File transfer protocol — sends data unencrypted by default.
(d) SMTP: Used for sending emails — can use SSL/TLS for secure transmission (SMTPS), but itself is not encryption protocol.

Topic: API Security – Rate Limiting

Q2: Rate limiting is a strategy used to control the number of requests a user or client can make to an API within a specific time period. What is the primary purpose of implementing rate limiting?

Options:
 (a) ✅ It prevents unauthorized access to the API
(b) It ensures that the API remains available and responsive for all users
(c) It allows developers to bypass authentication
(d) It increases the amount of data returned in each response

✅ Correct Answer: (a) It prevents unauthorized access to the API

Explanation:
 Rate limiting is used to control API traffic and prevent abuse or denial-of-service (DoS) attacks. By limiting how many requests a user or client can make within a certain time, the API avoids being overloaded.
Although it doesn’t directly authenticate users, it adds a layer of protection against unauthorized or excessive requests — helping to keep the API stable and available.

Other Options:
 (b) Ensuring API availability is a benefit, not the main purpose.
(c) Rate limiting never bypasses authentication; it works alongside it.
(d) It doesn’t affect how much data is sent — only how often requests are made.

💡 Trick:

“Authentication checks who you are — Rate limiting controls how much you can do.”

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Topic: Cloud Computing – Deployment Models & Security

Q3: Assume that you have recently started working for an organization that is transitioning to a cloud-based infrastructure. As part of IT governance, you are responsible for ensuring data security in the cloud environment. You need to choose the most secure cloud deployment model for an organization handling highly sensitive data. Which cloud deployment model is typically the most secure?

Options:
 (a) Public Cloud
(b) ✅ Private Cloud
(c) Hybrid Cloud
(d) Community Cloud

✅ Correct Answer: (b) Private Cloud

Explanation:
 A Private Cloud is owned, managed, and operated exclusively by a single organization. It offers dedicated resources, controlled access, and customized security policies, making it ideal for handling confidential or sensitive data (like finance, healthcare, or government information).
Organizations have full control over infrastructure, data governance, and compliance, reducing risks of data breaches compared to shared public environments.

Other Options:
 (a) Public Cloud: Shared infrastructure; cost-effective but less control → higher exposure to threats.
(c) Hybrid Cloud: Mix of public + private; improves flexibility but security depends on proper integration.
(d) Community Cloud: Shared by similar organizations (e.g., banks, universities); secure but not as isolated as private.

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Topic: Computer Networks – TCP 3-Way Handshake

Q4: After initializing a connection attempt to a remote server, a client application sends a SYN packet to request a reliable connection. What is the expected response from the server, assuming it is available and ready to accept the connection?

Options:
 (a) A FIN-ACK packet
(b) ✅ A SYN-ACK packet
(c) A RST packet
(d) An ACK packet

✅ Correct Answer: (b) A SYN-ACK packet

Explanation:
 In TCP (Transmission Control Protocol), a three-way handshake is used to establish a reliable connection between client and server:
1️⃣ Client → SYN: Client sends a SYN packet to initiate connection.
2️⃣ Server → SYN-ACK: Server acknowledges with SYN-ACK (acknowledge + synchronize).
3️⃣ Client → ACK: Client sends an ACK confirming connection established.

So, the server’s expected response to a SYN packet is a SYN-ACK, signaling readiness to establish communication.

Other Options:
 (a) FIN-ACK: Used during connection termination (not setup).
(c) RST: Sent when connection is refused or invalid.
(d) ACK: Used after SYN-ACK to complete handshake, not as first server response.

💡 Trick:

“SYN → SYN-ACK → ACK” = TCP connection established (3-way handshake).

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Topic: Network Security – Wi-Fi Encryption Protocols

Q5: A network administrator is tasked with selecting a secure wireless encryption protocol. Which of the following is considered the most secure for Wi-Fi networks?

Options:
 (a) WEP
(b) WPA2
(c) ✅ WPA3
(d) TKIP

✅ Correct Answer: (c) WPA3

Explanation:
 WPA3 (Wi-Fi Protected Access 3) is the latest and most secure wireless encryption standard. It uses 128-bit or 192-bit encryption, Simultaneous Authentication of Equals (SAE) for stronger password protection, and improved defense against brute-force attacks. It also offers forward secrecy, meaning even if a password is compromised later, past data remains secure.

Other Options:
 (a) WEP (Wired Equivalent Privacy): Outdated and easily hackable using basic tools.
(b) WPA2: Much stronger than WEP but still vulnerable to key reinstallation attacks (KRACK).
(d) TKIP (Temporal Key Integrity Protocol): Was used in WPA; now obsolete and insecure.

💡 Trick:

“WEP → Weak, WPA2 → Good, WPA3 → Best.”

Q:
 Assume that a developer is tasked with configuring a high-security Wi-Fi environment for a sensitive government project using Android devices.
The configuration must leverage WPA-Enterprise security and the highest encryption settings (Suite-B-192) for compliance.

The given wpa_supplicant.conf snippet is:

CONFIG_SAE=Y  

CONFIG_SUITEB=Y  

CONFIG_SUITEB192=Y

In this scenario, which is the incorrect configuration line that might potentially weaken the desired security level?

Options:
 A. ✅ CONFIG_SAE=Y is unnecessary since WPA-Enterprise does not integrate SAE.
B. CONFIG_SUITEB=Y is required to enable basic Suite-B cryptography.
C. CONFIG_SUITEB192=Y enables the highest level of security, Suite-B at 192-bit.
D. CONFIG_SUITEB=Y is redundant when CONFIG_SUITEB192=Y is also specified.

✅ Correct Answer: A. CONFIG_SAE=Y is unnecessary since WPA-Enterprise does not integrate SAE.

🧠 Explanation:

• SAE (Simultaneous Authentication of Equals) is part of WPA3-Personal, not WPA-Enterprise.
  
• WPA-Enterprise uses 802.1X / EAP authentication, not the SAE handshake.
  
• Enabling SAE in an enterprise setup can cause misconfiguration and reduce compatibility or weaken intended security.
  
• SUITEB192 activates the strongest encryption level (192-bit AES-GCM and SHA-384) — ideal for government-grade networks.
  

Other Options:

• B. CONFIG_SUITEB=Y → valid for enabling Suite-B 128-bit security.
  
• C. CONFIG_SUITEB192=Y → enables 192-bit encryption; correct.
  
• D. CONFIG_SUITEB=Y redundant with SUITEB192=Y → may be true but not a weakness — it’s a configuration overlap, not a vulnerability.
  

💡 Trick to Remember:

🔐 Enterprise = 802.1X (EAP)
 🧩 SAE = WPA3-Personal only
 ⚙️ For max security → use SUITEB192, skip SAE!

🧠 Wi-Fi Security – Summary Notes

🔹 1. Wi-Fi Encryption Standards

Trick 🧩:

WEP → WPA → WPA2 → WPA3 = weak → better → strong → strongest 💪
🔒 “WEP Weak, WPA2 Okay, WPA3 Ace!”

🔹 2. WPA3 Security Features

• SAE (Simultaneous Authentication of Equals): Prevents password-guessing/brute-force attacks.
  
• Forward Secrecy: Even if a password leaks later, old data stays safe.
  
• Stronger Encryption: 128-bit for personal, 192-bit for enterprise (Suite-B-192).
  

🔹 3. WPA3-Enterprise / Suite-B Configuration

Code snippet (example):

CONFIG_SAE=Y

CONFIG_SUITEB=Y

CONFIG_SUITEB192=Y

Incorrect Line:
 ✅ CONFIG_SAE=Y → Not needed for WPA-Enterprise; SAE is for WPA3-Personal.

Why?

• WPA-Enterprise uses 802.1X / EAP authentication, not SAE.
  
• For high-security government networks → use CONFIG_SUITEB192=Y (192-bit encryption).
  

Trick 💡:

🏢 Enterprise = 802.1X (no SAE)
 🏠 Personal = SAE handshake
 ⚙️ “SuiteB192 = Strongest WPA3 mode”

🔹 4. Related Term – TKIP

• TKIP (Temporal Key Integrity Protocol): Older encryption used in WPA; deprecated and insecure.
  

⚡ Final Shortcut Recap:

• WEP = Worst
  
• WPA2 = Good but can be hacked
  
• WPA3 = Best & Secure
  
• SAE = WPA3-Personal
  
• Suite-B-192 = WPA3-Enterprise (Gov-level security)
  
• TKIP = Trash, avoid 😅

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Topic: Network Security – Routing & Firewall Evasion Attacks

Q6: Assume your computer's data was stolen by hackers through your network by mentioning the route to be used by the packets. This was done to bypass security measures since the firewall didn’t analyze the source information properly. What is this type of attack called?

Options:
 (a) IP Address Spoofing
(b) ✅ Source Routing Attack
(c) Tiny Fragment Attack
(d) Drive-by Attack

✅ Correct Answer: (b) Source Routing Attack

Explanation:
 A Source Routing Attack occurs when the attacker manually specifies the path that network packets should take through routers — instead of allowing routers to determine the best route.
By doing this, the hacker can bypass security devices like firewalls or intrusion detection systems, which rely on normal routing paths to inspect traffic.
This type of attack manipulates the IP header’s source routing option to avoid detection and exfiltrate data.

Other Options:
 (a) IP Address Spoofing: Faking the source IP address to appear as a trusted system.
(c) Tiny Fragment Attack: Breaking malicious packets into small fragments to bypass firewall inspection.
(d) Drive-by Attack: Malicious code downloaded automatically when visiting a compromised website.

💡 Trick:

“When attacker controls the path of packets → it’s a Source Routing Attack.”

Topic: Network Security – Routing & Packet Manipulation Attacks

Q:
 Hackers attempt to intercept and manipulate data packets traveling across a network by inserting malicious routing information, allowing them to redirect traffic through their own systems.
This enables them to eavesdrop or alter data without detection.
What type of attack is this called?

Options:
 A. Packet Sniffing
B. IP Spoofing
C. DNS Spoofing
D. ✅ Routing Table Poisoning

✅ Correct Answer: (D) Routing Table Poisoning.

🧠 Explanation:

• Routing Table Poisoning occurs when an attacker injects false routing information into a router’s routing table.
  
• This causes network traffic to be misrouted — often through the attacker’s system — enabling data interception, packet modification, or traffic redirection.
  
• It’s a type of Man-in-the-Middle (MitM) attack at the network layer.
  

Other Options:

• A. Packet Sniffing: Only captures packets; does not alter routing or inject data.
  
• B. IP Spoofing: Fakes the source IP address, not the route.
  
• C. DNS Spoofing: Manipulates domain-to-IP mappings, not routing paths.

          ✅ Simple Trick to Remember:

📡 Router ko bewakoof bana de → Routing Table Poisoning
 🛣️ Packet me route likh de → Source Routing Attack

   Packet Sniffing = just listens to traffic. — Trick: “Wiretap the wire.”

   IP Spoofing = fake who sent it. — Trick: “Wear a fake sender mask.”

   DNS Spoofing = fake the address book. — Trick: “Change the map, send them    wrong.”

   Routing Table Poisoning = break the routers’ map. — Trick: “Poison the map, reroute the road.”

    Source Routing Attack = fake how it should travel. — Trick: “Tell the packet the path to take.”

   Tiny Fragment Attack = split to hide payload. — Trick: “Slice small so the guard misses pieces.”

   Drive-by Attack = visit site, get infected. — Trick: “Click the site, pick up the bug.”

   ARP Poisoning = trick LAN name-to-MAC mapping. — Trick: “Swap name tags

   On  the local network.”

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Q7:
 A web filtering service works with a firewall that stops user requests from leaving the network. The firewall queues the web filter, and based on the filter’s reply, it allows or denies the request.
Which of the following is not a disadvantage of using this service?

Options:
 A. The firewall system has to ensure that all requests made by users are copied to the web filter system, causing excess use of resources.
B. Any malicious activity on one system is likely to affect the other system also.
C. If the web filter starts failing, the network connectivity of the system is tampered with because of the trust relationship between web filters and the firewall.
D. ✅ There is a trust relationship which exists between the firewall system and the web filter.

✅ Correct Answer: (D) There is a trust relationship which exists between the firewall system and the web filter.

Explanation:

• The trust relationship between the firewall and web filter is essential for their coordination and is not a disadvantage — it enables proper communication and policy enforcement.
  
• The other options describe real disadvantages like resource overhead, dependency, and security risk from failure or compromise.
  

Other Options:

• (A) True disadvantage → high resource usage due to copying every request.
  
• (B) True disadvantage → compromise of one system can impact the other.
  
• (C) True disadvantage → web filter failure can disrupt network traffic.
  

💡 Trick:

“Trust relationship = necessary link, not a drawback.”

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Topic: Cloud & Networking – Email Transmission Protocols

Q8:
 Assume that a company wants to ensure secure and reliable email transmission for its cloud-based email service. Which protocol should they implement?

Options:
 A. IMAP
B. POP3
C. ✅ SMTP
D. HTTPS

✅ Correct Answer: (C) SMTP (Simple Mail Transfer Protocol)

Explanation:

• SMTP is the standard protocol used to send (transmit) emails between mail servers and from client → server.
  
• For secure transmission, it’s combined with TLS/SSL → SMTPS (port 465 or 587).
  
• Ensures reliable delivery, queuing, and retry mechanisms in case of failure.
  

Other Options:

• IMAP (Internet Message Access Protocol): Used to receive and manage emails from a server, not for sending.
  
• POP3 (Post Office Protocol v3): Used to download emails to a local client, not to send them.
  
• HTTPS: Used for secure web browsing, not for email transport.
  

💡 Trick:

✉️ Send = SMTP
 📥 Read/Receive = IMAP/POP3
 🔒 Add “S” (TLS/SSL) for security → SMTPS, IMAPS, POP3S

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Topic: Cloud Computing – Hybrid Cloud Security & Connectivity

Q9:
An enterprise is adopting a hybrid cloud model, where they combine on-premise infrastructure with public cloud services. To securely connect these environments and ensure data integrity, what solution should they implement?

Options:
A. Public Key Infrastructure (PKI)
B. ✅ Secure hybrid connectivity with VPN
C. Serverless architecture
D. Data encryption with asymmetric keys

✅ Correct Answer: (B) Secure hybrid connectivity with VPN

🧠 Explanation:

• A Hybrid Cloud combines on-premises (private) and public cloud infrastructure.
  
• To allow these two environments to communicate securely, companies use a VPN (Virtual Private Network) or dedicated connection (like AWS Direct Connect, Azure ExpressRoute).
  
• This ensures:
  

• Encrypted communication between both networks
  
• Data integrity and privacy
  
• Seamless resource access across both environments
  

Other Options:

• A. PKI: Provides identity and encryption certificates — supports security, but doesn’t itself connect two environments.
  
• C. Serverless Architecture: Is a deployment model, not a connectivity or security solution.
  
• D. Asymmetric Encryption: Protects data itself, not the network link between cloud and on-prem systems.
  

💡 Trick to Remember:

🔒 Hybrid cloud = 2 networks (private + public)
To link them securely → Use VPN (Virtual Private Network)

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opic: Network Security – Access Control

Q10:
Which method is used to prevent unauthorized devices from connecting to a network?

Options:
A. ✅ MAC Filtering
B. DNS Spoofing
C. IP Forwarding
D. ARP Poisoning

✅ Correct Answer: (A) MAC Filtering

🧠 Explanation:

• MAC Filtering allows or blocks network access based on the device’s unique MAC address (Media Access Control address).
  
• The network administrator maintains an allowed list (whitelist) of trusted MAC addresses.
  
• If a device’s MAC is not on the list → connection is denied.
  
• Commonly used in Wi-Fi routers and enterprise networks for access control.
  

Other Options:

• DNS Spoofing: Attack where fake DNS responses redirect users to malicious sites — not used for protection.
  
• IP Forwarding: Normal network routing process — not a security control.
  
• ARP Poisoning: Cyberattack where attackers alter MAC-IP mappings to intercept traffic.
  

💡 Trick to Remember:

“MAC Filtering = MAC-based Access Control”
Only approved devices connect; others get blocked.

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Topic: DevOps / Container Security – Resource Isolation

Q10:
Assume that an application relies on multiple hardware peripherals and requires strict isolation from other running containers to maintain data integrity and operational security.
To achieve this, the team configures the kernel so that each container is allocated specific hardware resources, limiting visibility of non-allocated devices to prevent unauthorized access.

What is the most critical factor in maintaining operational security and preventing resource contention among containers?

Options:
A. Ensuring that the host OS scheduler prioritizes CPU cycles equally for all containers.
B. ✅ Configuring the kernel to enforce strict resource isolation and limit peripheral access to only allocated devices for each container.
C. Using virtualization software to dynamically allocate additional memory resources to containers.
D. Allowing containers to share network interfaces to optimize data transmission rates.

✅ Correct Answer: (B) Kernel-level resource isolation and restricted device access

🧠 Explanation:

• Containers share the same OS kernel, so without proper isolation, one container can interfere with or access another’s resources.
  
• The kernel’s cgroups (control groups) and namespaces are used to isolate:
  

• CPU, memory, I/O, and devices per container.
  
• Prevent resource contention (fighting over CPU/memory).
  
• Ensure security and data separation.
  

Thus, configuring the kernel to strictly enforce resource isolation is key.

Other Options:

• A: Equal CPU cycles ≠ security — this affects performance fairness, not isolation.
  
• C: Dynamic memory allocation is performance tuning, not security or isolation.
  
• D: Sharing network interfaces reduces isolation — increases risk.
  

💡 Trick to Remember:

🧱 “Container Security starts at the Kernel.”
Use Namespaces + cgroups → ensure isolation, not sharing.

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Topic: Network Security – Virtual Private Networks (VPNs)

Q11:
Assume that an employee at a multinational organization is working from home and needs to access the company’s internal network to retrieve some files.
Which type of Virtual Private Network (VPN) will be best suitable for this case?

Options:
A. ✅ Remote Access VPN
B. Site-to-Site VPN
C. MPLS VPN
D. PPTP VPN

✅ Correct Answer: (A) Remote Access VPN

🧠 Explanation:

• A Remote Access VPN allows individual users (like employees working from home) to securely connect to the company’s internal network over the Internet.
  
• It encrypts data traffic between the user’s device and the corporate network, ensuring privacy and security.
  
• Common protocols: IPSec, SSL, or TLS.
  

Other Options:

• B. Site-to-Site VPN: Connects two entire networks (e.g., between two office branches), not for single remote users.
  
• C. MPLS VPN: Used by large enterprises for multi-site private WAN connections, managed by ISPs — not for home users.
  
• D. PPTP VPN: Outdated and insecure VPN protocol — replaced by L2TP/IPSec or SSL VPN.
  

💡 Trick to Remember:

🏠 Remote worker → Remote Access VPN
🏢 Office-to-office → Site-to-Site VPN

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Topic: Cloud Computing – Virtualization Technologies

Q12:
 Assume that in a cloud infrastructure that requires running multiple isolated environments on a single physical server, which technology is primarily used?

Options:
 A. ✅ Virtual Machines
B. Containers
C. Bare Metal
D. Serverless

✅ Correct Answer: (A) Virtual Machines

🧠 Explanation:

• Virtual Machines (VMs) use a hypervisor to divide one physical server into multiple isolated virtual environments.
  
• Each VM has its own OS, CPU, memory, and storage, allowing secure and independent operation.
  
• This provides strong isolation — ideal for multi-tenant or multi-environment setups in cloud data centers.
  

Other Options:

• B. Containers: Share the host OS kernel → faster but less isolated than VMs.
  
• C. Bare Metal: No virtualization; direct hardware usage (only one environment).
  
• D. Serverless: Runs code in ephemeral environments, not persistent isolated servers.
  

💡 Trick to Remember:

🖥️ “One physical, many virtual = Virtual Machines.”
 🧱 Containers → lightweight sharing;
🏗️ VMs → full isolation with own OS.

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Topic: Networking – VPN Topologies

Q13:
 An organization has two geographically separate offices — Office A and Office B.
They need to allow all users in Office A to securely access resources in Office B, and vice versa,
as if both were on the same local network.
Which VPN topology is most appropriate for this scenario?

Options:
 A. Remote Access VPN
B. Client-to-Site VPN
C. ✅ Site-to-Site VPN
D. SSL VPN

✅ Correct Answer: C. Site-to-Site VPN

🧠 Explanation:

• A Site-to-Site VPN securely connects two networks (sites) over the Internet,
  so devices at both ends can communicate as if on one LAN.
  
• It uses dedicated VPN gateways (like routers or firewalls) to establish a permanent tunnel between offices.
  
• Best for branch connectivity in enterprises.
  

Other Options:

• A. Remote Access VPN: Used for individual users (e.g., employees working from home).
  
• B. Client-to-Site VPN: Same idea — connects one user (client) to office network.
  
• D. SSL VPN: Used for secure web-based remote access, not whole-office connectivity.

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Topic: Networking – VPN Types

Q14:
 Assume that an employee at a multinational organization is working from home and needs to access the company’s internal network to retrieve files.
Which type of Virtual Private Network (VPN) is best suitable for this scenario?

Options:
 A. ✅ Remote-Access VPN
B. Site-to-Site VPN
C. MPLS VPN
D. PPTP VPN

✅ Correct Answer: A. Remote-Access VPN

🧠 Explanation:

• A Remote-Access VPN allows individual users (e.g., employees working from home) to securely connect to the company’s internal network over the Internet.
  
• It uses encryption and authentication so the remote user appears as if connected locally to the office LAN.
  
• Best for work-from-home, traveling employees, or mobile workforce.
  

Other Options:

• B. Site-to-Site VPN: Connects two office networks, not individuals.
  
• C. MPLS VPN: Used by ISPs for large-scale enterprise routing, not personal access.
  
• D. PPTP VPN: An older, insecure VPN protocol (mostly deprecated).

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🧠 VPN Types – Shortcut Notes

Q15) Assume that a messaging system uses symmetric encryption to secure communication between two parties.
The encryption and decryption processes are as follows:

• Each party encrypts messages before sending them using a shared secret key.
  
• Messages are decrypted by the receiving party using the same shared secret key.
  

If an attacker can send a specially crafted message to one party and analyze the resulting encrypted message, which of the following techniques is most likely to compromise the secret key?

Options:
A. Analyzing patterns in intercepted encrypted messages
B. ✅ Comparing the crafted message's encrypted output with previous encrypted messages
C. Performing a brute force attack on intercepted messages
D. Matching message lengths to guess the content

✅ Correct Answer: B. Comparing the crafted message's encrypted output with previous encrypted messages

🧠 Explanation:

• This attack is known as a Chosen Plaintext Attack (CPA).
  
• The attacker chooses specific plaintexts (crafted messages) and observes the corresponding ciphertexts.
  
• By comparing the results, the attacker can sometimes deduce patterns or parts of the secret key, especially if the encryption algorithm or mode is weak.
  

💡 Trick to Remember:

✉️ “If the attacker chooses the message → it’s a Chosen Plaintext Attack.”
They craft → encrypt → compare → crack 🔐

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Topic: Cloud Computing – Resource Management & Scalability

Q16:
Assume that an e-commerce website is experiencing sudden traffic spikes during a flash sale.
The platform needs to adjust resources automatically to handle the increased load without manual intervention.
Which cloud feature should be prioritized?

Options:
A. ✅ Auto-scaling
B. Static IP Allocation
C. Multi-tenancy
D. Load Balancing

✅ Correct Answer: A. Auto-scaling

🧠 Explanation:

• Auto-scaling automatically adjusts (adds or removes) computing resources like servers or containers based on real-time traffic and load.
  
• It ensures high performance during peak demand and cost savings during low traffic — no manual action required.
  

Other Options:

• B. Static IP Allocation: Fixes an IP address — unrelated to scaling or traffic management.
  
• C. Multi-tenancy: Means multiple users share the same infrastructure securely (not about scaling).
  
• D. Load Balancing: Distributes traffic across instances but doesn’t create or remove instances automatically.
  

💡 Trick to Remember:

☁️ Load Balancing = spread the load
⚙️ Auto-scaling = add/remove servers automatically
🔁 Auto-scaling = the cloud “auto-adjusts” itself to demand!

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– OSI Model (Ethernet cables & Wi-Fi signals)

Q17:
 Assume that an internet connection is established by a user.
This network connects a computer, smartphone, and smart TV to a router using Ethernet cables and Wi-Fi signals.
Which layer of the OSI model is responsible for connecting these physical media (cables/wireless)?

Options:

A. Physical Layer
B. Network Layer
C. Data Link Layer
D. Application Layer

✅ Correct Answer:

A. Physical Layer

🧠 Explanation:

⚡️ Trick to Remember OSI Layers (Top → Bottom):

🧩 “All People Seem To Need Data Processing”

✅ Question 18:
 Your marketing lead requests a list of employees from the South region for an internal campaign.
Which Excel formula allows you to generate this list dynamically from the dataset?
(You’re using Excel 365 or later, so dynamic array functions are supported.)

Options:

A. =IF(H2:H9="South", B2:B9)
 B. =FILTER(B2:B9, H2:H9="South")
 C. =XLOOKUP("South", H2:H9, B2:B9)
 D. =INDEX(B2:B9, MATCH("South", H2:H9, 0))

✅ Correct Answer:

B. =FILTER(B2:B9, H2:H9="South")

🧠 Explanation:

📘 Result Example:

If your dataset is:

✅ Formula →
=FILTER(B2:B9, H2:H9="South")

Output:

George  

Hina

💡 Quick Trick to Remember:

🧩 FILTER = Find All
 💬 Use FILTER when you want all matches, not just the first one.

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Question19:
 Which Excel feature allows you to create custom calculations and summaries within a Pivot Table?

Options:

A. Calculated Fields
B. Calculated Items
C. Slicers
D. Grouping

✅ Correct Answer:

A. Calculated Fields

🧠 Explanation:

📘 Trick to Remember:

💡 Mini Example:

Suppose Pivot Table fields:

• Revenue
  
• Cost
  

You can add a Calculated Field like:
➡️ = Revenue - Cost
 to create a new field “Profit” directly inside the Pivot Table.

In short:
 🧮 Calculated Field → when you need a new column of custom calculations inside a Pivot Table.

—------------------------------------------------------------------------------------------------------------------

Question20:
 In a corporate network, data packets are transmitted between routers and switches to ensure proper delivery across different segments. The OSI model is used to understand how data moves through the network.
Which layer of the OSI model is responsible for establishing logical paths and routing data packets between different network segments?

Options:

A. Data Link Layer
B. Network Layer
 C. Transport Layer
D. Session Layer

✅ Correct Answer:

B. Network Layer

🧠 Explanation:

💡 Shortcut Concept:

🛰️ Network Layer = Routing Layer
 → It decides “how data travels” using IP addresses and routing tables between different networks.

So, routers work at the Network Layer, handling packet forwarding and path selection.

—--------------------------------------------------------------------------------------------------------------------

Question21:
Consider that in a cloud computing environment, which security measure helps protect user accounts by requiring them to provide two different types of identification before granting access?

Options:

A. Firewalls
B. Encryption
C. ✅ Multi-Factor Authentication
D. Antivirus Software

✅ Correct Answer:

C. Multi-Factor Authentication (MFA)

🧠 Explanation:

Multi-Factor Authentication (MFA) adds an extra layer of security by requiring users to verify their identity using two or more factors before granting access.

👉 These factors are typically:

1. Something you know – Password or PIN
   
2. Something you have – Phone, OTP, security token
   
3. Something you are – Fingerprint, face scan, voice
   

Even if one factor (like a password) is compromised, MFA prevents unauthorized access.

⚙️ Other Options Explained:

Question 22:
 Consider that a small business uses a Ring Topology.
If a single workstation goes down, what impact will it have on the network?

Options:

A. Minimal impact, network reroutes traffic
B. Network becomes isolated
C. Network slows down
D. ✅ Network breaks completely

✅ Correct Answer:

D. Network breaks completely

🧠 Explanation:

In a Ring Topology, each device is connected to exactly two other devices, forming a circular path.
➡️ Data travels in one direction (or both, in dual-ring).
➡️ If any single device or cable fails, the entire network breaks because the loop is interrupted.

📉 Hence, a single workstation failure = complete network failure.

💡 Trick to Remember All Topologies Easily

Question 23:
 What is the process of converting data into a secure format to prevent unauthorized access called?

Options:

A. Encryption
B. Authentication
C. Authorization
D. Compression

✅ Correct Answer:

A. Encryption

🧠 Explanation (Simple Notes):

Encryption means changing normal (readable) data — called plaintext — into a scrambled, unreadable form — called ciphertext — so unauthorized users can’t understand it.
It’s used for protecting data at rest (stored) and data in transit (sent over networks).

🔑 Only those with the key can decrypt (unlock) the data back into readable form.

⚙️ Other Options Explained:

💡 Shortcut Trick:

🧠 “Encrypt = Encode for Eyes only!”
→ Converts data into code that only the right key can decode 🔐

Question24)

Assume that an application relies on a series of hardware peripherals and requires strict isolation from other running containers to maintain data integrity and operational security.
To ensure this, the development team implements a kernel-level configuration where each container is allocated specific hardware resources, limiting visibility of non-allocated devices.

What is the most critical factor in maintaining operational security and preventing resource contention among containers?

Options:

(a) Ensuring that the host OS scheduler prioritizes CPU cycles equally for all containers
(b) ✅ Configuring the kernel to enforce strict resource isolation and limit peripheral access to only the allocated devices for each container
(c) Using virtualization software to dynamically allocate additional memory resources
(d) Allowing containers to share network interfaces to optimize transmission rates

✅ Correct Answer:

👉 (b) Configuring the kernel to enforce strict resource isolation and limit the peripheral access

💡 Explanation:

• Containers share the same OS kernel, unlike V

• 1-Line Trick to Remember

• 🧱 Containers = Share Kernel but Isolated by Namespaces & Cgroups.
   So whenever question says “strict isolation” → mark kernel-level isolation ✅

—------------------------------------------------------------------------------------------------------------------------

Question25):
 Assume a network administrator wants to assign IP addresses dynamically to devices in a network. Which protocol (introduced in 2003) is used for this purpose?

🧩 Options:

A. DNS
B. DHCP
C. ARP
D. ICMP

✅ Correct Answer:

B. DHCP (Dynamic Host Configuration Protocol)

🧠 Explanation (Short Notes):

• DHCP automatically assigns IP addresses to devices on a network.
  
• It’s an updated version of BOOTP (used earlier).
  
• Introduced in RFC 2131 and standardized in early 2000s.
  
• It helps avoid manual IP configuration and IP conflicts.
  

⚙️ How it Works (DHCP Steps — DORA Trick 🧩):

🔁 (DORA = DHCP handshake process)

⚡ Other Options (for contrast):

—------------------------------------------------------------------------------------------------------------------------

Question25):
 A startup is concerned about unpredictable expenses due to variable cloud usage.
Which cloud feature should they implement to manage and predict costs more accurately?

🧩 Options:

A. Auto-scaling
B. Reserved Instances
C. Load Balancing
D. Content Delivery Network (CDN)

✅ Correct Answer:

B. Reserved Instances

🧠 Explanation (Short Notes):

• Reserved Instances (RIs) = Long-term cloud resource booking at a fixed, discounted rate.
  
• They allow businesses to predict and control cloud costs, unlike pay-as-you-go pricing.
  
• Usually available in AWS, Azure, GCP, etc.
  
• Example: Book a server for 1 or 3 years → up to 70% cheaper and predictable bills 💰
  

⚡ Other Options (for contrast):

💡 Memory Trick:

“If you want stable bills, make a reservation — Reserved Instances 🔒💵”

⚙️ Extra Tip (for exam):

• Auto-scaling = Handles load spikes automatically.
  
• Reserved Instances = Handles budget predictability.
  
• Spot Instances = Cheapest, but unpredictable availability

—----------------------------------------------------------------------------------------------------------

Question 26):
 Assume a company needs a security solution where the firewall acts as an intermediary, inspecting all outgoing and incoming traffic between the user’s device and the internet.
Which type of firewall is most suitable for this requirement?

🧩 Options:

(a) Packet Filtering Firewall
(b) ✅ Proxy Firewall
(c) Circuit-Level Gateway
(d) Application Firewall

🧠 Answer: (b) Proxy Firewall

⚡ Trick to Remember:

🧱 “Proxy = Parda (middleman)”
 If the firewall sits between user and internet — checking everything like a parda (screen) before passing —
it’s always a Proxy Firewall!

💡 Short Explanation:

• Proxy firewall = middleman 👀 between your PC & the web.
  
• It hides your real IP, inspects data deeply (Layer 7).
  
• Used for secure corporate environments.
  

🧭 Example:
When you visit a website — request goes → Proxy Firewall → Internet → back through Proxy Firewall.
It checks everything both ways 🔄.

🚀 Other Firewall Types Trick Table:

COMPUTER SCIENCE

Q1 – HTTP Methods (Data Retrieval)
 Assume a mobile app needs to retrieve a list of all available restaurants from a food delivery service API.
The app should only read data and not change anything on the server.
Which common HTTP method is most appropriate for this type of data retrieval?

Options:
 A. POST
B. PUT
C. DELETE
D. ✅ GET

✅ Correct Answer: D. GET

Explanation of All Options:

HTTP Methods – Short Notes (for quick revision):

• GET: Data retrieve karta hai. Server par koi change nahi karta. Example – get all users.
  
• POST: Server par naya data create karta hai. Example – add new restaurant.
  
• PUT: Existing resource replace karta hai (full update). Example – update complete profile.
  
• PATCH: Resource ka partially update karta hai. Example – change only email or phone.
  
• DELETE: Resource ko remove karta hai. Example – delete user record.
  
• HEAD: Sirf headers/metadata return karta hai, body nahi. Example – check if resource exists.
  
• OPTIONS: Batata hai server kaunse methods support karta hai. Example – “Allow: GET, POST”.
• CONNECT: Proxy tunnel setup karta hai (mostly HTTPS). Example – SSL proxy request.
  
• TRACE: Request ko echo back karta hai debugging ke liye. Rarely used.

OOPs – Polymorphism

Q2 : Which concept is being used in the given code?

class A {

  int a;

  void sum() {

    a++;

  }

  void sum(int a) {

    a = a + a;

  }

};

Options:
(a) Abstraction
(b) Encapsulation
(c) Inheritance
(d) ✅ Polymorphism

✅ Correct Answer: (d) Polymorphism

Explanation:

• Yah code method overloading ka example hai — same method name sum() with different parameters.
• This is Compile-time (Static) Polymorphism in Java/C++.
• Compiler decide karta hai kis method ko call karna hai based on argument list.

Other Options (for revision):

• Abstraction: Implementation details ko hide karna (via abstract class/interface).
• Encapsulation: Data aur methods ko ek class me band karna, using access modifiers (private/public).
• Inheritance: Ek class dusri class ke features inherit karti hai (extends, :).
  

💡 Quick Tip:

“Same name, different form = Polymorphism”
Overloading → Compile-time,
Overriding → Runtime.

Q3: During the development of an application, a developer encounters an error message indicating that the API endpoint they are trying to access is not found.
Which HTTP status code is most likely associated with this error?

Options:
A. 404
B. 500
C. 403

✅ Correct Answer: A. 404 (Not Found)

Short Explanation:

• 404 Not Found → Server reachable hai, lekin requested endpoint/resource exist nahi karta.
  Example: Wrong URL, deleted API path.

Topic: HTTP / Web Fundamentals – Status Codes (Tricks + Explanation)

✅ 1xx – Information (Bas “Shuruwaat” phase)

Trick: “1xx = Message Received, Work in Progress”

• 100 Continue → Server ne kaha: “Haan bhai, data bhejna jaari rakho.”
• 101 Switching Protocols → “Protocol badal raha hoon, jaise HTTP → WebSocket.”

✅ 2xx – Success (Sab sahi chal raha hai!)

Trick: “2xx = All Good”

• 200 OK → Perfect! Data mil gaya.
• 201 Created → Naya resource successfully bana.
• 204 No Content → Kaam ho gaya, par koi reply body nahi (jaise delete success).

💡 Remember: “2xx = Green Signal ✅”

✅ 3xx – Redirection (Raasta badal do)

Trick: “3xx = Chalo idhar se jao!”

• 301 Moved Permanently → URL hamesha ke liye badal gaya.
• 302 Found → Temporary redirect.
• 304 Not Modified → Cached data use kar lo.

💡 Remember: “3xx = Redirect kar diya.”

✅ 4xx – Client Error (Tumse galti hui 😅)

Trick: “4xx = Client ki galti”

• 400 Bad Request → Request format galat.
• 401 Unauthorized → Login/Token chahiye bhai!
• 403 Forbidden → Login sahi, par permission nahi.
• 404 Not Found → URL galat ya resource gayab.
• 405 Method Not Allowed → Wrong HTTP method (e.g., POST instead of GET).
• 429 Too Many Requests → Server ne bola: “Bas bhai! Rate limit khatam.”

💡 Remember:

404 = "Lost Path"
403 = "Gate Closed"
401 = "ID Missing"

✅ 5xx – Server Error (Ab server pareshaan 😓)

Trick: “5xx = Server ki galti”

• 500 Internal Server Error → Kuch toh gadbad hai server me.
• 502 Bad Gateway → Upstream se galat response aaya.
• 503 Service Unavailable → Server overloaded or maintenance.
• 504 Gateway Timeout → Server ne time pe jawab nahi diya.

💡 Remember:

“5xx = Not your fault, server ki fault.”

Topic: OOPs – Polymorphism (Overloading vs Overriding)

Q4:
Assume that a Java application having a class name TeaMac that can handle different types of tea. The class has a method to boil tea based on the tea selected.

public class TeaMac {

  public Coffee boilTea(ChooseTea choosed) {

    switch (choosed) {

      case GREEN_TEA:

        return boilgreentea();

      default:

        // default code

    }

  }

  public List boilTea(ChooseTea choosed) {

    List teas = new ArrayList(number);

    for (int i=0; i<number; i++) {

      teas.add(boilTea(choosed));

    }

    return teas;

  }

}

Options:
(a) ✅ Static polymorphism
(b) Dynamic polymorphism
(c) Late binding
(d) Method overriding

✅ Correct Answer: (a) Static Polymorphism

Explanation:

• Yah code method overloading ka example hai → same method name boilTea() but different parameter/return type.
• Compiler decide karta hai compile time pe kaunsa method call hoga → isiliye Static (Compile-time) Polymorphism.
• Overloading same class me hoti hai, inheritance ka use nahi hota.
  

Other Options:
(b) Dynamic polymorphism: Runtime pe decide hota hai → jab child class parent ki method ko override karti hai.
(c) Late binding: Runtime binding = dynamic polymorphism hi hota hai.
(d) Method overriding: Jab subclass parent class ki same signature wali method redefine kare → ye bhi runtime polymorphism hai.

🧠 Quick Notes:

• Method Overloading → Compile-time polymorphism → Static binding → Same class.
  
• Method Overriding → Runtime polymorphism → Dynamic/Late binding → Parent-child classes.
  

💡 Trick:

“Compile-time = Overloading (same class)”
“Runtime = Overriding (different class)”

Q:5
During deployment, assume a DevOps engineer observes that a containerized application experiences high latency.
What approach should the engineer take first to rectify the issue?

Options:
A. Increase the CPU and memory limits
B. ✅ Analyze the network traffic and logs
C. Restart the container
D. Reduce the number of containers

✅ Correct Answer: B. Analyze the network traffic and logs

Short Explanation:

• Latency cause identify karna sabse pehla step hai.
• Logs aur network metrics help karte hain ye samajhne me ki delay application, network, ya resource bottleneck se aa raha hai.
• Direct scaling (CPU/memory) ya restart karna temporary fix hai, permanent solution nahi.

Other Options:

• A. Increase CPU/memory: Tabhi jab metrics show kare resource saturation.
• C. Restart container: Sirf short-term fix; reason clear nahi hota.
• D. Reduce containers: Wrong step — load aur badh sakta hai.

💡 Trick:

“DevOps mantra: Investigate before you scale.”
Logs → Metrics → Then tuning.

Topic: DevOps – CI/CD Pipeline (Artifact Management)

Q6: When a successful build in the Continuous Integration pipeline, assume that the compiled and packaged application (e.g., a JAR file, Docker image, or rpm package) needs to be stored in a central, versioned repository. This ensures that only approved, tested, and immutable binaries are used for deployments to various environments (development, staging, production). Which DevOps building block addresses the secure storage, versioning, and retrieval of these build outputs?

Options:
 (a) Source Code Management
(b) Database Management
(c) ✅ Artifact Management
(d) Container Orchestration

✅ Correct Answer: (c) Artifact Management

Explanation:
 Artifact Management securely stores, versions, and retrieves build outputs like JARs, Docker images, or RPMs to ensure consistent, tested, and immutable artifacts are deployed.
Tools include JFrog Artifactory, Sonatype Nexus, and AWS CodeArtifact.

Other Options:
 (a) Source Code Management – handles source code (Git, SVN), not build binaries.
(b) Database Management – manages structured data, not application builds.
(d) Container Orchestration – manages container deployment and scaling (Kubernetes), not artifact storage.

💡 Trick:
 “SCM = Source | Artifact Repo = Build Output | Orchestration = Deployment.”

Q7: What will be the output of the given code when the user clicks the button?

<body>

  <button onclick="myFunction(this)">Test onclick attribute!</button>

  <script type="text/javascript">

    function myFunction(button) {

      document.write(button.getAttribute("onClick", 1));

   }

  </script>

</body>

Options:
 (a) True
(b) False
(c) ✅ myFunction(this)
(d) None of the given options
✅ Correct Answer: (c) myFunction(this)

🔹 Step 1: Code kya kar raha hai?

HTML me ek button banaya gaya hai:

<button onclick="myFunction(this)">

•  Yahaan "onclick" ka matlab hai → jab user button click karega, tab myFunction(this) chalega.
  (Yani ye button click hone par JavaScript function call karta hai.)

🔹 Step 2: this ka matlab kya hai?

• Yahaan this keyword button ko hi refer karta hai.
  Matlab jab button click hota hai, this usi button ka reference ban jaata hai.
  So myFunction(this) me → button parameter = <button> element khud.
  

🔹 Step 3: Function ke andar kya ho raha hai?

document.write(button.getAttribute("onClick", 1));

• button.getAttribute("onClick") ka matlab hai:
  “Button ke andar likha hua onClick attribute ka value nikal do.”
  

Button ke andar likha tha:

onclick="myFunction(this)"

 So getAttribute("onClick") ye string return karega:

myFunction(this)

🔹 Step 4: document.write(...) kya karega?

• Ye page pe likh dega / print kar dega jo string return hui hai.

To jab button click karega, output banega 👇

myFunction(this)

✅ Final Answer: (c) myFunction(this)

💡 Extra Knowledge:

• getAttribute("onClick") → HTML attribute ka actual text value deta hai.
  

Agar function me likha hota:

button.getAttribute("id")

•  To wo button ka id return karta.
  
• document.write() → normally testing ke liye use hota hai, production code me avoid karte hain.
  

Aise question me hamesha soch:
👉 Step 1 – Function kab call ho raha hai?
👉 Step 2 – Parameter kya pass hua (this)?
👉 Step 3 – getAttribute() kya fetch kar raha hai?
👉 Step 4 – document.write() kya print karega?

—---------------------------------------------------------------------------------------------------------------------------------------------------------

Q8: Assume that in a grocery store, the management wants a Java program to manage and display item types in stock. A Java class GroceryStore is written to create instances for “Apple” and “Milk”, using constructors with no parameters and one parameter respectively. What will be the correct output of this program?

class GroceryStore {

  String itemType;

  GroceryStore() {

    itemType = "Apple";

  }

  GroceryStore(String itemType) {

    this.itemType = itemType;

  }

  public void getItemType() {

    System.out.println("Item Type: " + itemType);

  }

  public static void main(String[] args) {

    GroceryStore obj1 = new GroceryStore();

    GroceryStore obj2 = new GroceryStore("Milk");

    obj1.getItemType();

    obj2.getItemType();

  }

}

✅ Output:

Item Type: Apple

Item Type: Milk

Explanation:

• Constructor Overloading:
  

• The default constructor (no parameters) initializes itemType = "Apple".
  
• The parameterized constructor sets itemType to the value passed ("Milk").
  

• In main(), two objects are created:
  

• obj1 → uses default constructor → Apple
  
• obj2 → uses parameterized constructor → Milk
  

• Each call to getItemType() prints the corresponding item type.
  

💡 Trick:

“Constructor with no args → default value, Constructor with args → custom value.”

—---------------------------------------------------------------------------------------

Topic: DevOps – Continuous Delivery & Deployment

Q9:
 An e-commerce company updates its website weekly by adding new features and fixing bugs using an Agile development approach.
After each update, the new version is automatically deployed to the live environment.
Which key DevOps practice is being implemented to ensure rapid and frequent releases?

Options:
 A. The practice involves automating the process of releasing software to production frequently and reliably.
B. Continuous Integration focuses on merging code changes regularly to prevent conflicts.
C. Continuous Testing ensures that automated tests are run continuously to validate code quality.
D. Monitoring involves tracking the application's performance and user activity after deployment.

✅ Correct Answer: (A) Continuous Deployment (or Continuous Delivery)

🧠 Explanation:

• In this scenario, the software is automatically deployed to production after every update — no manual intervention.
  
• This is the core concept of Continuous Deployment, a DevOps practice that automates the release process.
  
• It ensures fast, reliable, and frequent software updates — ideal for Agile environments.
  

Other Options:

• B. Continuous Integration (CI): Involves merging code frequently, but doesn’t deploy automatically.
  
• C. Continuous Testing (CT): Focuses on running tests automatically — supports CI/CD but not deployment itself.
  
• D. Monitoring: Happens after deployment, not part of the release automation.

—---------------------------------------------------------------------------------------------------------------------------------

Topic: DevOps / Testing – Jest Command-Line Options

Q10:
 You are configuring Jest to run tests with specific command-line options for coverage reporting and test execution.
Which Jest command-line option would you use to generate a coverage report in HTML format?

Options:
 A. coverageReporters text.html
 B. collectCoverage true coverageReporters=text,html
 C. ✅ --coverage --coverageReporters=text,html
 D. --collectCoverageFrom=src --coverageFilesReporters=text.html

✅ Correct Answer: (C) --coverage --coverageReporters=text,html

🧠 Explanation:

• Jest provides the --coverage flag to collect code coverage data during test execution.
  
• The --coverageReporters option specifies the formats of coverage output.
  
• Common reporters → "text", "html", "lcov".
  
• The "html" format generates a detailed visual coverage report in /coverage/index.html.
  

Example Command:

jest --coverage --coverageReporters=text,html

Other Options:

• A: Missing the required double hyphens (--) for CLI flags.
  
• B: Looks like JSON config format, not a command-line option.
  
• D: Incorrect syntax and invalid flag names.
  

💡 Trick to Remember:

🧪 For Jest CLI:
✅ --coverage → to collect data
✅ --coverageReporters=html → to view it visually in browser

—---------------------------------------------------------------------------------------------------------------------------------

Topic: RESTful API Design – HTTP Methods & URL Structure

Q11:
 Assume a development team is designing a RESTful API to manage a product catalog for an e-commerce platform.
They need to create an endpoint that retrieves detailed information about a specific product using its unique product ID.
Which HTTP method and URL structure best aligns with RESTful principles for this operation?

Options:
 A. POST /products/{id}/details
 B. GET /product.details?id={id}
 C. PUT /products/{id}/fetch
 D. ✅ GET /products/{id}

✅ Correct Answer: D. GET /products/{id}

🧠 Explanation:

• RESTful APIs use standard HTTP methods that map to CRUD operations:
  

• GET → Retrieve data
  
• POST → Create data
  
• PUT/PATCH → Update data
  
• DELETE → Remove data
  

• Here, we only need to retrieve product info → so GET is correct.
  
• /products/{id} is the resource path to that specific product (id = unique identifier).

—------------------------------------------------------------------------------------------------

Topic: Cloud Computing – Hybrid Cloud Security & Connectivity

Q12:
 An enterprise is adopting a hybrid cloud model, combining on-premise infrastructure with public cloud services.
To securely connect these environments and ensure data integrity, what solution should they implement?

Options:
 A. Public Key Infrastructure (PKI)
B. ✅ Secure hybrid connectivity with VPN
C. Serverless Architecture
D. Data Encryption with Asymmetric Keys

✅ Correct Answer: B. Secure Hybrid Connectivity with VPN

🧠 Explanation:

• A Hybrid Cloud links private (on-premise) and public cloud resources.
  
• To ensure secure data transfer between these two environments, organizations use a VPN (Virtual Private Network).
  
• VPN provides an encrypted tunnel between networks, maintaining data confidentiality, integrity, and security.
  

Other Options:

• A. PKI: Used for authentication and digital certificates, not direct network connectivity.
  
• C. Serverless Architecture: Refers to cloud computing execution model, not networking security.
  
• D. Asymmetric Encryption: Protects data itself, not the connection between environment

—----------------------------------------------------------------------------------------------------------------------------------------------

Topic: DevOps – Container Performance & Resource Optimization

Q13:
 Assume a DevOps engineer notices that a containerized application consumes excessive memory, leading to performance issues.
What is the recommended approach to address this issue?
Select the correct option from the given choices.

Options:
 A. Increase the memory limit for the container
B. Use a larger base image for the container
C. Reduce the number of replicas of the container
D. ✅ Analyze the application code for memory leaks

✅ Correct Answer: D. Analyze the application code for memory leaks

🧠 Explanation:

• If a container consistently uses more memory than expected, the problem is likely inside the application itself, not the container.
  
• The first step should be to check for memory leaks or inefficient code using profiling tools (like Prometheus, Grafana, or language profilers).
  
• Simply increasing the memory limit might hide the root cause instead of fixing it.
  

Other Options:

• A. Increasing memory limits is a temporary workaround, not a fix.
  
• B. Larger base image doesn’t solve runtime memory issues.
  
• C. Reducing replicas just decreases availability, not memory use per container.
  

💡 Trick to Remember:

🧠 “If memory grows without reason → it’s leaking season!”
Always debug → profile → fix the code, not just add more memory.

—-------------------------------------------------------------------------------------------------------------------------------------------

Question14):
Consider that a team wants to improve deployment speed and reduce downtime when updating their containerized application.
Which practice should the team adopt in this scenario?

🧩 Options:

(a) Increase the number of replicas
(b) Disable the health checks
(c) ✅ Use rolling updates with health checks
(d) Use a larger base image

🧠 Correct Answer: (c) Use rolling updates with health checks

Quick Trick Summary Table:

COMMON APPLICATIONS

Q1: Assume a developer writes a program that needs to create a new process and run a different executable file. Which pair of system calls in a UNIX OS fulfill this requirement?

Options:

(a) create() and run()

(b) ✅ fork() and exec()

(c) fork() and wait()

(d) spawn() and terminate()

✅ Correct Answer: (b) fork() and exec()

Explanation: fork() creates a new child process (a copy of the parent). After that, exec() replaces the child’s memory with a new executable program, effectively running a different file. This combo is the standard way to create and execute a new process in UNIX.

Other Options:

(a) create() and run(): No such system calls in UNIX.

(c) fork() and wait(): Used when parent waits for child to finish, not to run a new executable.

(d) spawn() and terminate(): Used in Windows OS, not UNIX.

💡 Trick: > “In UNIX: fork → clone, exec → replace.”

—-------------------------------------------------------------------------------------------------------------------

Topic: MS PowerPoint – Slide Navigation Control

Q2: You're building a training module in MS PowerPoint and want to restrict navigation so that each slide is viewed sequentially with narration. Which setting provides the desired control?

Options:
 (a) Add hyperlinks to the "next" button and "prev" navigation
(b) Disable "click to advance" and use "custom show"
(c) ✅ Enable "Browsed at a kiosk (full screen)" mode
(d) Use "Loop continuously" with auto transitions

✅ Correct Answer: (c) Enable "Browsed at a kiosk (full screen)" mode

Explanation:
 The “Browsed at a kiosk (full screen)” option in PowerPoint locks the presentation so users can’t manually skip slides by clicking or pressing keys. Navigation can only happen using action buttons or links that you define — perfect for training modules, quizzes, or guided tutorials with narration.

Other Options:
 (a) Hyperlinks (Next/Prev): Allow navigation, but don’t restrict users from skipping slides manually.
(b) Disable click + Custom show: Useful for specific slide sequences, but not for restricting all navigation.
(d) Loop continuously: Just restarts the presentation automatically; doesn’t enforce sequence or control navigation.

💡 Trick:

“For controlled, step-by-step PowerPoint flow → Use Kiosk Mode.”

—------------------------------------------------------------------------------------

Topic: Computer Architecture – CPU Operations

Q3:
 As a computer architect, you are designing the control unit of a CPU. You need to specify how data is moved from the accumulator to the memory. Which of the following best describes this operation?

Options:
 (a) The process of transferring data from the accumulator to memory is called a register transfer.
(b) The process of transferring data from the accumulator to memory is called a memory read operation.
(c) ✅ The process of transferring data from the accumulator to memory is called a memory write operation.
(d) The process of transferring data from the accumulator to memory is called an instruction fetch.

✅ Correct Answer: (c) Memory Write Operation

Explanation:

• The accumulator is a CPU register that temporarily holds data during arithmetic or logic operations.
  
• When we move (store) data from the accumulator → memory, the CPU is writing data to memory.
  
• Hence, this is called a Memory Write Operation.
  

Other Options:

• (a) Register transfer: Movement of data between CPU registers, not between CPU and memory.
  
• (b) Memory read: Means fetching data from memory → CPU, opposite direction.
  
• (d) Instruction fetch: CPU fetching instruction from memory, not data.
  

💡 Trick:

“CPU → Memory = Write”
“Memory → CPU = Read”

—------------------------------------------------------------------------------------------------------------

Q4:
 To create a document template for repeated use, which of the given file formats should you save the document in?

Options:
 A. .doc
 B. .docx
 C. ✅ .dotx
 D. .txt

✅ Correct Answer: (C) .dotx

🧠 Explanation:

• A template in MS Word is a pre-designed file that can be reused to create multiple similar documents (like invoices, resumes, reports).
  
• Templates store layout, styles, and default text, but not the actual content.
  
• MS Word template format is:
  

• .dotx → Word Template (without macros)
  
• .dotm → Word Template (with macros)
  

Other Options:

• .doc / .docx: Normal Word document formats, not reusable templates.
  
• .txt: Plain text file — no formatting or layout features.
  

💡 Trick to Remember:

“T” in .dotx = Template
 Use .dotx for reusable document designs.

—------------------------------------------------------------------------------------------------

Topic: Computer Architecture – Device Controllers & Data Transfer

Q5:
In a computer system, data is transferred between the CPU and peripheral devices through a shared bus controlled by device controllers.
To improve data transfer speed and reduce latency, the system incorporates controllers with dedicated high-speed buffers.
Which of the following device controllers is most suitable for this purpose?

Options:
A. Wireless Controller
B. USB (Universal Serial Bus) Controller
C. ✅ SATA (Serial Advanced Technology Attachment) Controller
D. Ethernet Controller

✅ Correct Answer: (C) SATA (Serial Advanced Technology Attachment) Controller

🧠 Explanation:

• SATA controllers are designed for high-speed data transfer between the CPU and storage devices (HDDs/SSDs).
  
• They use dedicated buffers and Direct Memory Access (DMA) to reduce CPU overhead and latency.
  
• Ideal for fast, reliable, high-throughput communication with minimal delay — exactly what the question describes.
  

Other Options:

• A. Wireless Controller: Used for Wi-Fi or Bluetooth — not high-speed direct data transfer to CPU.
  
• B. USB Controller: Slower and shared bus; general-purpose connectivity, not optimized for sustained high throughput.
  
• D. Ethernet Controller: Handles network data, not CPU–peripheral transfer inside the system.

—----------------------------------------------------------------------------------------------------------------------------

Topic: MS PowerPoint – Animation & Transitions

Q6:
 Jane wants to create a slide that illustrates a progression over time using icons, text, and lines.
She wants it to look visually dynamic without manually animating each step.
Which MS PowerPoint feature can help speed up this process?

Options:
 A. Use Slide Zoom feature to create dynamic progress slides quickly.
B. Use SmartArt Process layout and apply by Paragraph animation.
C. ✅ Apply the Morph transition across duplicated slides for smooth flow.
D. Create a custom layout with background images and animation triggers.

✅ Correct Answer: (C) Apply the Morph transition across duplicated slides for smooth flow.

🧠 Explanation:

• The Morph Transition automatically animates changes in objects, text, or shapes between two similar slides.
  
• It creates smooth motion and progression without manual animation.
  
• Perfect for showing growth, timeline, or transformation visually.
  

Other Options:

• A. Slide Zoom: Used for interactive navigation between slides, not for continuous progression.
  
• B. SmartArt Process: Shows static flow diagrams, limited motion.
  
• D. Custom Layouts: Require manual animation — opposite of what Jane wants.
  

💡 Trick to Remember:

🌀 “Morph = Magic Move” → smooth, automatic animation between similar slides.

—-------------------------------------------------------------------------------------------------------------------

Topic: Operating System – Process Management & CPU Registers

Q7:
 During a context switch, the OS saves the state of the currently running process and loads the state of the next one.
Which crucial CPU register, responsible for holding the address of the next instruction to be fetched, must be saved and restored during this operation?

Options:
 A. Stack Pointer (SP)
B. General Purpose Register (GPR)
C. ✅ Program Counter (PC)
D. Instruction Register (IR)

✅ Correct Answer: (C) Program Counter (PC)

🧠 Explanation:

• The Program Counter (PC) holds the memory address of the next instruction the CPU will execute.
  
• During a context switch, the OS must save the PC value of the current process and restore it later so that the process resumes exactly where it left off.
  

Other Options:

• A. Stack Pointer (SP): Stores the top address of the stack; also saved but not responsible for next instruction address.
  
• B. GPR: Used for temporary data, not instruction sequencing.
  
• D. IR (Instruction Register): Holds the current instruction being executed, not the next one.
  

💡 Trick to Remember:

🧠 PC = “Program’s Current location” — tells CPU where to go next!
 In context switch → Save PC = “pause location”, Restore PC = “resume here”.

—-------------------------------------------------------------------------------------------------------------

Topic: DevOps / Cloud – Containerization

Q8:
 Consider that a software development team is implementing containerization to drive application deployment by encapsulating applications and their dependencies.
What characteristic separates containers in the context of software development and deployment?
Select the correct answer from the given choices.

Options:
 A. Lightweight VMs with a dedicated hypervisor
B. A logically separate network within servers
C. ✅ Part of the same OS instance as the hypervisor
D. Virtual computers running under a hypervisor

✅ Correct Answer: C. Part of the same OS instance as the hypervisor

🧠 Explanation:

• Containers share the same operating system kernel as the host OS and run as isolated processes.
  
• This makes them lightweight, faster to start, and more resource-efficient than virtual machines.
  
• They package only the application and its dependencies, not a full OS.
  

Other Options:

• A. ❌ Containers don’t have a hypervisor — they run on a container engine like Docker.
  
• B. ❌ Networking concept, not related to containerization.
  
• D. ❌ Describes Virtual Machines (VMs) which each have their own OS under a hypervisor.
  

💡 Trick to Remember:

🐳 Containers share OS → light & fast
 💻 VMs have OS → heavy & isolated

—------------------------------------------------------------------------------------------------------------------

Topic: Operating System – Key Properties & Compatibility

Q9:
Consider you are a software developer working on a new application for a large corporation.
Your application is expected to run on a variety of computers with different hardware specifications and operating systems.
You must ensure compatibility and smooth operation on all these systems.
Which property of an operating system is most important for you to consider?

Options:
A. User Interface
B. Security
C. ✅ Device Management
D. Resource Allocation

✅ Correct Answer: C. Device Management

🧠 Explanation:

• Device Management is the OS property that handles communication between hardware devices and software applications.
  
• It ensures that the application can interact with different hardware configurations (printers, storage, network cards, etc.) without rewriting code for each system.
  
• This enables portability and compatibility across different computers.
  

Other Options:

• A. User Interface: Defines user interaction, not hardware compatibility.
  
• B. Security: Important, but unrelated to cross-device compatibility.
  
• D. Resource Allocation: Deals with CPU/memory distribution, not hardware variation.
  

💡 Trick to Remember:

⚙️ “Different devices? → Device Management!”
It’s the OS property that makes your app run smoothly everywhere.

CODIND MCQS

Topic: SQL – LIKE Operator (Pattern Matching)

Q1: The question asks which of the given list of names will be displayed as a result of the following SQL command:
SELECT emp_name FROM employees WHERE emp_name LIKE '%a%';

✅ Correct Answer: Names containing the alphabet ‘a’

Explanation:
 The condition LIKE '%a%' returns all employee names that contain the letter ‘a’ anywhere in the name. The % wildcard matches any number of characters (before or after ‘a’). Example: Sara, Raj, Aman will match, but Eric, John won’t.

Important About LIKE:

• LIKE is used for pattern-based filtering in SQL queries.
• % → matches any sequence of characters (zero or more).
• _ → matches exactly one character.
• 'a%' → names starting with ‘a’.
• '%a' → names ending with ‘a’.
• '%a%' → names containing ‘a’.
• '__a' → names having ‘a’ at third position.
• In MySQL, LIKE is case-insensitive by default; in PostgreSQL, use ILIKE for case-insensitive matching.

💡 Trick:

% = many characters, _ = one character
 “Use %a% to find anything with ‘a’ anywhere.”

Q2: Which optimization technique will improve the query performance the most?                   SELECT * FROM CUSTOMERS WHERE State='xyz' OR State='abc';
Options:
 (a) Adding more rows to the table
(b) ✅ Creating an index on the small column
(c) Using a Foreign Key on the small column
(d) Denormalizing the table
✅ Correct Answer: (b) Creating an index on the small column
Explanation: Indexing the State column allows the database to find matching rows quickly instead of scanning the whole table, improving performance in WHERE queries.

Extra Concept – Normalization:
 Normalization organizes data into smaller related tables to reduce redundancy and maintain data integrity. It ensures efficient storage and easier maintenance.

• 1NF: Remove repeating groups; each column holds a single value.
• 2NF: Remove partial dependency (every non-key depends on the full key).
• 3NF: Remove transitive dependency (non-key depends only on the key).
  💡 Trick: “1NF – single value, 2NF – full key, 3NF – only key.”
  Normalization improves consistency, while indexing improves query speed.

—----------------------------------------------------------------------------------------------------------------------

Topic: SQL – Sorting Query Results (ORDER BY Clause)

Q3: Which SQL statement is used to display records in ascending order from a table?

Options:
 (a) Select * from [table] order by [col];
(b) Select * from [table] sort by [col] ASC;
(c) ✅ Select * from [table] order by [col] ASC;
(d) Select * from [table] group by [tbl] ASC;

✅ Correct Answer: (c) Select * from [table] order by [col] ASC;

Explanation:

• The ORDER BY clause in SQL is used to sort query results.
  
• By default, sorting is ascending (ASC) unless DESC (descending) is specified.
  

Example:

SELECT * FROM employees ORDER BY salary ASC;

•  → Displays employee records sorted by salary in ascending order (lowest to highest).
  

Other Options:
 (a) order by [col] works too (ASC is optional) but option (c) explicitly states ascending order, which matches the question.
(b) sort by is invalid syntax in SQL.
(d) group by is used for aggregating data, not for sorting.

💡 Trick:

“Sorting in SQL → always use ORDER BY (ASC for low→high, DESC for high→low).”     —(SQL me SORT BY nahi hota.)

—----------------------------------------------

Q4:
 Assume Dustin is using a browser that does not support the <video> element and wants to create a video element with a source, controls, and a fallback message.
Which option denotes the correct HTML code Dustin can use for this purpose?

Options:
 A.

<video src="video.mp4" type="video/mp4" controls>

  <p>Sorry, your browser doesn't support the video element.</p>

</video>

B. ✅

<video controls>

  <source src="video.mp4" type="video/mp4">

  <p>Sorry, your browser doesn't support the video element.</p>

</video>

C.

<video>

  <source src="video.mp4" type="video/mp4" controls>

  <p>Sorry, your browser doesn't support the video element.</p>

</video>

D.

<video src="video.mp4" controls>

  Sorry, your browser doesn't support the video element.

</video>

✅ Correct Answer: (B)

Explanation:
 Option B correctly follows the standard structure of the HTML <video> tag:

• The controls attribute enables play, pause, and volume options.
  
• The <source> tag defines the video file and format (src + type).
  
• The text or elements inside <video> serve as fallback content, shown if the browser does not support the video element.
  

Why others are wrong:

• (A): type attribute doesn’t belong in <video> — it should be in <source>.
  
• (C): controls must be on <video>, not on <source>.
  
• (D): Missing <source> tag; not the proper structure for modern HTML5 video.
  

💡 Trick:

Always write →
<video controls>
 → <source src="..." type="...">
 → fallback message inside.

—-----------------------------------------------------------

Topic: JavaScript – Array.map() Method

Q5:
 What will be the output of the given code?

var my_arr = [3, 16, 2, 18];

function myFunction(elem) {

  return (elem + 5);

}

document.write(my_arr.map(myFunction));

Options:
 A. 3,16,2,18
B. ✅ 8,21,7,23
C. True
D. False

✅ Correct Answer: (B) 8,21,7,23

🧠 Explanation:

1. my_arr = [3, 16, 2, 18]
   
2. map() method → calls myFunction() for each element in the array and returns a new array.
   
3. Inside the function:
   return elem + 5;
    So each element increases by 5.
   

➡ Calculation:

• 3 + 5 = 8
  
• 16 + 5 = 21
  
• 2 + 5 = 7
  
• 18 + 5 = 23
  

Final Output: [8, 21, 7, 23]

💡 Notes for Revision:

• .map() → applies a function on each array element, returns new array.
  
• Does not modify the original array.
  
• Shortcut:
  
  
  “map = transform each item and return a new list.”
• —---------------------------------------------------------------------------------

Topic: Database Optimization – Query Performance

Q7:
 Assume a retail company notices that queries to search for customers by Email are running very slowly because the Customers table has over 5 million rows.
The query is:

SELECT * FROM Customers WHERE Email = "abc@example.com";

Which optimization technique will improve the query performance the most?

Options:
 A. Adding more rows to the table
B. ✅ Creating an index on the Email column
C. Using a Foreign Key on the Email column
D. Denormalizing the table

✅ Correct Answer: (B) Creating an index on the Email column

🧠 Explanation:

• When searching a specific value (like Email), database has to scan all rows if there’s no index — that’s called a full table scan, which is slow for large tables.
  
• By creating an index on the Email column, the database can quickly locate matching rows using the index (like a book’s index for fast lookup).
  
• It drastically improves query speed without changing data structure.
  

Other Options:

• A. Adding more rows: Makes the query even slower — not optimization.
  
• C. Foreign Key: Maintains referential integrity between tables, not for searching performance.
  
• D. Denormalization: Used for complex joins or analytical queries, not for simple lookups by one column.

—----------------------------------------------------------------------------------------------------------------------

Q8:
 What will be the output of the depicted code?

class Test {

    public int x = 45;

    public int y;

    public double z;

    public void F1(int a) {

        y = a;

    }

    public double F2() {

        return 5;

    }

    public static void main(String args[]) {

        Test t = new Test();

        t.x = 9;

        t.y = 18;

        t.z = 3;

        t.F1(21);

        System.out.println(t.F2());

    }

}

Options:
 A. 9
B. 21
C. ✅ 5.0
D. Compilation Error

✅ Correct Answer: (C) 5.0

🧠 Explanation:

• When the object t is created, default x=45.
  
• Then it changes:
  

• t.x = 9;
  
• t.y = 18;
  
• t.z = 3;
  

• Then t.F1(21); → assigns y = 21.
  
• Finally, t.F2() returns 5 (of type double) → prints 5.0
  

💡 Concept Recap:

• F1() → updates variable y.
  
• F2() → returns a constant 5.0.
  
• Nothing is printed except what’s inside System.out.println().
  

✅ Output:

5.0

Topic: SQL – Sorting Query Results

Q9:
 Which of the following statements will you use to retrieve items in ascending order from a table in SQL?

Options:
 A. SELECT * FROM [table] ORDER BY [tbl_clm];
 B. SELECT * FROM [table] SORT BY [tbl_clm];
 C. ✅ SELECT * FROM [table] ORDER BY [tbl_clm] ASC;
 D. SELECT * FROM [table] GROUP BY [tbl_clm] ASC;

✅ Correct Answer: (C) SELECT * FROM [table] ORDER BY [tbl_clm] ASC;

—------------------------------------------------------------------

Q10:
 What is the final value of total after executing the following pseudocode?

FUNCTION incrementByThree(n)

    RETURN n + 3

END FUNCTION

total = 0

FOR i = 1 TO 3

    total = total + incrementByThree(i)

END FOR

DISPLAY total

Options:
 A. 7
B. 10
C. 15
D. 18

✅ Correct Answer: C. 15

🧠 Explanation (Step-by-step):

Loop runs i = 1 to 3, so three iterations.

 — the total is 15.

—---------------------------------------------------------------------

Topic: HTML5 – Canvas Element

Q11:
 What does the following line in the given <canvas> tag indicate?

<canvas id="myCanvas">

  HTML5 Canvas not supported.

</canvas>

Options:
 A. A content for the server
B. ✅ A comment for incompatible browsers
C. A comment for Internet Explorer and Opera
D. All of the given options

✅ Correct Answer: B. A comment for incompatible browsers

🧠 Explanation:

• Anything written inside the <canvas> ... </canvas> tags is fallback content.
  
• This content is displayed only when the browser doesn’t support the HTML5 <canvas> element.
  
• It acts like a backup message (not a comment), helping users understand that their browser is outdated.
  

Example:
 If a browser supports <canvas>, it shows the drawing area.
If it doesn’t, it will show:
👉 “HTML5 Canvas not supported.”

Other Options:

• A. ❌ Not related to the server.
  
• C. ❌ Not specific to IE or Opera only — it applies to all unsupported browsers.
  
• D. ❌ Incorrect — only option B is true.
  

💡 Trick to Remember:

🧩 Canvas inner text = Fallback Message
 If the browser can’t draw, it shows the text instead!

—------------------------------------------------------------

Question 1 – SQL JOIN Concept

🧠 CASE 1 – When all data is in one table (EMPLOYEE)

Q12:

Write an SQL query to display:

The ID, Name, Department name, and Basic salary of employees working in the ‘HR’ department.

Your output should have 4 columns:

EMPID, EMPNAME, DEPTNAME, BASIC.

Table: EMPLOYEE

✅ Query:

SELECT EMPID, EMPNAME, DEPTNAME, BASIC

FROM EMPLOYEE

WHERE DEPTNAME = 'HR';

📊 Output:

Explanation:

• SELECT chooses which columns to display.
  
• FROM EMPLOYEE tells SQL the table name.
  
• WHERE DEPTNAME = 'HR' filters only HR department employees.
  
• Since DEPTNAME is inside EMPLOYEE, no JOIN is needed.

—--------------------------------------------------------

Q:
 Write an SQL query to display the ID, Name, Department name, and Basic salary of employees working in the ‘HR’ department.
Your output should have these 4 columns:
EMPID, EMPNAME, DEPTNAME, BASIC.

🧩 Table 1: EMPLOYEE

🧩 Table 2: DEPARTMENT

✅ Query (Correct – Using INNER JOIN)

SELECT

    E.EMPID,

    E.EMPNAME,

    D.DEPTNAME,

    E.BASIC

FROM

    EMPLOYEE E

INNER JOIN

    DEPARTMENT D ON E.DEPTID = D.DEPTID

WHERE

    D.DEPTNAME = 'HR';

📊 Output

🧠 Why INNER JOIN (not LEFT or RIGHT)?

💡 Trick to Remember

🔹 INNER JOIN → Intersection → “Only common data.”
🔹 LEFT JOIN → All from left, plus matches.
🔹 RIGHT JOIN → All from right, plus matches.

—-----------------------------------------------------

💡 1️⃣ What is a Trigger?

A trigger in SQL is like an automatic action that runs when something happens in a table.
That “something” = INSERT, UPDATE, or DELETE.

📍 Think of it like:

“Whenever someone deletes an employee, automatically write that info somewhere else.”

💡 2️⃣ Trigger Syntax (simple pattern)

CREATE TRIGGER trigger_name

{BEFORE | AFTER} {INSERT | UPDATE | DELETE}

ON table_name

FOR EACH ROW

BEGIN

   -- code to execute

END;

So:

• BEFORE → runs before the action happens.
  
• AFTER → runs after the action happens.
  
• FOR EACH ROW → runs for every row affected.
  

💡 3️⃣ Example Explained (Our Question)

Requirement:
 When a row is deleted from Employees, make a log in AuditLog.

✅ Correct trigger:

CREATE TRIGGER after_employee_delete

AFTER DELETE ON Employees

FOR EACH ROW

INSERT INTO AuditLog (EmpID, DeletedOn)

VALUES (OLD.EMPID, NOW());

💬 Step-by-step Logic:

1. Action: Someone deletes a row from Employees.
   
2. Trigger Type: AFTER DELETE → So this will run after the deletion happens.
   
3. What it does: Inserts a new record into AuditLog with:
   

• OLD.EMPID → The ID of the deleted employee.
  
• NOW() → The current time of deletion.
  

🧠 4️⃣ What does OLD and NEW mean?

💡 Trick to remember:
👉 DELETE → record gone → use OLD
 👉 INSERT → new record → use NEW

💡 5️⃣ How to Identify Trigger Type in Questions:

🧠 Shortcut Memory Line:

“AFTER DELETE → OLD record ko yaad karo (log karo)” 😄
“BEFORE INSERT → NEW record ko check karo (validate karo)”

Question 11:
 Consider that a company wants an automatic log whenever an employee record is deleted.

The schema is:

CREATE TABLE Employees (

  EMPID INT PRIMARY KEY,

  Name VARCHAR(50)

);

CREATE TABLE AuditLog (

  LogID INT PRIMARY KEY AUTO_INCREMENT,

  EmpID INT,

  DeletedOn DATETIME

);

Which trigger definition correctly implements this in MySQL?

✅ Correct Answer:

CREATE TRIGGER after_employee_delete

AFTER DELETE ON Employees

FOR EACH ROW

INSERT INTO AuditLog (EmpID, DeletedOn)

VALUES (OLD.EMPID, NOW());

🧠 Explanation (Short Notes for Revision):

• AFTER DELETE: Trigger runs after a row is deleted from Employees.
  
• FOR EACH ROW: Ensures trigger runs for every deleted record, not once per query.
  
• OLD: Refers to the deleted row’s values.
  
• NOW(): Captures the current date and time of deletion.
  
• INSERT INTO AuditLog: Stores the deleted employee’s ID and timestamp.
  

⚙️ Quick Trick:

🧩 Think “AFTER DELETE → OLD is gone”
 → Because the record is deleted, use OLD (not NEW).
💡 AFTER = OLD | BEFORE = NEW

—----------------------------------------------------------------

Question12:

What will be the output of the following pseudo code?

1 Integer p,q,r

2 Set p = 1, q = 8, r = 9

3 q = (11 + 9) & q

4 p = q + q

5 Print p + q + r

Step-by-Step Solution:

1️⃣ Start values:
 p = 1, q = 8, r = 9

2️⃣ Line 3 → q = (11 + 9) & q

• (11 + 9) = 20
  
• 20 & 8 → Bitwise AND
  
• Convert to binary:
  

• 20 → 10100
  
• 8 → 01000
   AND → 00000 → 8 (only bit 8 matches) ❌ wait check bits carefully:
  

20 = 10100

8  = 01000

-------------

AND=00000 → 0 ✅

✅ q = 0

3️⃣ Line 4 → p = q + q
 → p = 0 + 0 = 0

4️⃣ Line 5 → Print p + q + r
 → 0 + 0 + 9 = 9 ✅

✅ Final Output → 9

⚙️ Quick Recognition Trick:

🧠 Practice in Mind

1. 6 & 3 → both have 2 → 2
   
2. 6 | 3 → combine all bits → 7
   
3. 5 ^ 3 → different bits → 6
   
4. 8 >> 1 → half → 4
   
5. 5 << 1 → double → 10
   

💡 Trick to Solve Without Paper (Mental Flow):

🧩 Convert each number to nearest power of 2 →
🧩 For &, take common part.
🧩 For |, take combined part.
🧩 For ^, take unique bits.
🧩 For << or >>, multiply/divide by 2.

—---------------------------------------------------------------------------------------------------------------

Question 13:
 Which of the following codes is appropriate for autoplay?

🧩 Options:

(a)

<audio autoplay>

  <source src="test.mp3">

  <source src="test.ogg">

</audio>

(b)

<audio autoplay>

  <source src="test.mp3's">

  <source src="test.ogg">

</audio autoplay>

(c)

<audioplay>

  <source src="test.mp3">

  <source src="test.ogg">

</audioplay>

(d)

<audio>

  <controls>

    <source src="test.mp3">

    <source src="test.ogg">

  </controls>

</audio>

✅ Correct Answer: (a)

<audio autoplay>

  <source src="test.mp3">

  <source src="test.ogg">

</audio>

Explanation:

• The autoplay attribute in HTML <audio> automatically plays the audio when the page loads.
  
• <source> tags are used to define different formats (like .mp3, .ogg) for browser compatibility.
  
• The tag must be <audio>, not <audioplay> or nested <controls>.
  

⚡ Trick to Remember:

🧠 Auto = Start automatically!
 Whenever you see <audio autoplay> or <video autoplay>,
think — “Play without pressing play!” ▶️

—---------------------------------------------------------------------

Coding Questions

Question Statement:
Given a string S, count the frequency of each character. For each character, use the largest even number less than or equal to its frequency (if it appears 5 times, use 4). Find the character with the highest such even count, and the character with the lowest odd count (odd frequencies only). Return the difference: (max even count) - (min odd count).

Example 1:
Input: aarthu
Output: 1

Example 2:
Input: aniarnkabuhaywa
Output: 3

Code

import java.util.*;

public class UserMainCode {

    public int fruitfrequency(String input) {

        Map<Character, Integer> freq = new HashMap<>();

        for (char c : input.toCharArray()) {

            freq.put(c, freq.getOrDefault(c, 0) + 1);

        }

        int maxEven = 0;

        int minOdd = Integer.MAX_VALUE;

        for (int count : freq.values()) {

            int evenVal = count - (count % 2);

            if (evenVal > maxEven) maxEven = evenVal;

            if (count % 2 == 1 && count < minOdd) minOdd = count;

        }

        return maxEven - minOdd;

    }

}----------------------------------------------------------

🧩 Code Summary:

import java.util.*;

➡ Imports HashMap and other collection classes from java.util package.

public class UserMainCode {

➡ Class ka naam (Accenture exam me fixed hota hai).

public int fruitfrequency(String input) {

➡ Function jo ek String input lega aur int result (difference) return karega.

Map<Character, Integer> freq = new HashMap<>();

➡ HashMap banaya har character ka frequency (count) store karne ke liye.
Key → character, Value → us character ki frequency.

for (char c : input.toCharArray()) {

    freq.put(c, freq.getOrDefault(c, 0) + 1);

}

➡ String ke har character par loop chala.
toCharArray() → string ko char array me convert karta hai.
getOrDefault(c, 0) → agar char pehli baar aa raha hai to 0 lo.
+1 → count badha ke map me store karo.
👉 Result: Map me sabhi characters ke frequency aa gaye.

int maxEven = 0;

int minOdd = Integer.MAX_VALUE;

➡ Dono variable comparison ke liye:

• maxEven → sabse bada even frequency
  
• minOdd → sabse chhoti odd frequency (initially max value taaki pehla odd update ho)
  

for (int count : freq.values()) {

➡ Map ke har frequency value par loop.

int evenVal = count - (count % 2);

➡ Agar frequency odd hai to usse nearest chhote even number me convert karo.
(Example: 5 → 4, 3 → 2, 4 → 4)

if (evenVal > maxEven) maxEven = evenVal;

➡ Sabse bada even frequency store karo.

if (count % 2 == 1 && count < minOdd) minOdd = count;

➡ Agar frequency odd hai aur ab tak mile sabse chhoti odd se chhoti hai → update minOdd.

return maxEven - minOdd;

➡ Final answer = largest even frequency − smallest odd frequency.

⚙️ Working Example

Input → "aarthu"
 freq = {a=2, r=1, t=1, h=1, u=1}
 maxEven = 2 (a=2)
minOdd = 1 (r,t,h,u all 1)
✅ Output → 2 - 1 = 1

—------------------------------------------------------------

🍎Q2) New Question (Fruit Frequency – REVERSED VERSION)

Now asks:

Return absolute difference between (max odd frequency) and (min even frequency).

So logic is same, just reversed roles:
Earlier → biggest even − smallest odd
Now → biggest odd − smallest even (and take absolute value)

code==

import java.util.*;

public class Avi {

    public int fun1(String input) {

        Map<Character, Integer> freq = new HashMap<>();

        // Count frequency of each character

        for (int i = 0; i < input.length(); i++) {

            char c = input.charAt(i);

            freq.put(c, freq.getOrDefault(c, 0) + 1);

        }

        int minEven = Integer.MAX_VALUE;

        int maxOdd = 0;

        // Check frequencies

        for (int count : freq.values()) {

            if (count % 2 == 0 && count < minEven)

                minEven = count;

            if (count % 2 == 1 && count > maxOdd)

                maxOdd = count;

        }

        return Math.abs(maxOdd - minEven);

    }

    public static void main(String[] args) {

        Avi obj = new Avi();

        System.out.println(obj.fun1("aarthu")); // Output: 1

    }

}

—-------------------------------------------------------------------------------------------------------------------------

Frontend

🧱 1️⃣ HTML BASICS

📘 Structure

<!DOCTYPE html>

<html>

<head>

  <title>My Page</title>

</head>

<body>

  <h1>Hello!</h1>

</body>

</html>

💡 Meaning:

• <head> → info (title, links, scripts)
  
• <body> → actual visible content
  

🧩 Important Tags

🆔 id vs class

🧠 Trick:
 ➡️ ID = Individual
 ➡️ CLASS = Common

🎨 2️⃣ CSS BASICS

📘 Syntax

.box {

  width: 100px;

  height: 100px;

  background-color: yellow;

  border: 2px solid red;

}

💡 Common Properties

⚡ 3️⃣ BASIC JAVASCRIPT

✅ 1. Button Click

<button onclick="sayHi()">Click Me</button>

<script>

function sayHi() {

  alert("Hello from JavaScript!");

}

</script>

🧠 Trick → "onclick" calls function on click.

✅ 2. Get Input and Show Output

<input id="user" type="text" placeholder="Enter name">

<button onclick="showName()">Show</button>

<p id="result"></p>

<script>

function showName() {

  let name = document.getElementById("user").value;

  document.getElementById("result").innerText = "Hello, " + name + "!";

}

</script>

✅ 3. Change Style

<p id="text">Change my color</p>

<button onclick="changeColor()">Click</button>

<script>

function changeColor() {

  document.getElementById("text").style.color = "blue";

}

</script>

✅ 4. Add Class on Click (like your Tiger/Lion example)

<img id="photo" src="cat.jpg" width="100">

<style>

.green-border { border: 3px solid green; }

</style>

<script>

document.getElementById("photo").onclick = function() {

  this.classList.add("green-border");

};

</script>

💡 4️⃣ JQUERY VERSION (Short & Easier)

📘 Add CDN before using:

<script src="https://code.jquery.com/jquery-3.6.0.min.js"></script>

✅ 1. Button Click