ELECTRON DEVICES

1. In an IC technology, dry oxidation as compared to wet oxidation produces

  1. Inferior quality oxide with a lower growth rate
  2. Superior quality oxide with a higher growth rate
  3. Superior quality oxide with a lower growth rate
  4. Inferior quality oxide with a higher growth rate

Ans:     

2. When the frequency of the input signal to a CMOS gate is increased, the average power dissipation

  1. Decreases
  2. Increases
  3. Does not change
  4. Decreases exponentially

Ans:     

3. Which of the following is not associated with a PN junction?

  1. Charge storage capacitance
  2. Junction capacitance
  3. Depletion capacitance
  4. Channel length modulation

Ans:     

4. Zener diode breakdown voltage ___________ with temperature

  1. Increases
  2. Constant
  3. Decreases
  4. May increase or decrease

Ans:     

5. For an ac supply voltage with 60 Hz frequency, the ac ripple at the output of HWR, FWR with centre tapped transformer and Bridge rectifier respectively

  1. 60,60,60
  2. 60,120,180
  3. 60,120,60
  4. 60,120,120

Ans:     

6. A Si ingot is doped with 1016 arsenic atoms per cm3. Find its fermi level from the bottom of the conduction band at room temperature (300oK), when effective density of states of silicon are 2.8 x 1019 cm-3?

  1. 0.105 eV
  2. 0.206 eV
  3. 0.354 eV
  4. 0.456 eV

Ans:     

7. Which one of the following figure represents the cut-off region of NPN or PNP transistor?

ED7.PNG

Ans:     

8. A conducting line on an IC chip is 2.8 mm long and has a rectangular cross section 1µm x 4µm. A current of 5 mA produces a voltage drop of 100 mV across the line. If the electron mobility is 500 cm2/V-sec, the electron concentration is _____

  1. 4.38 x 1021 cm-3 
  2. 4.38 x 1027 cm-3 
  3. 3.98 x 1021 cm-3 
  4. 4.29 x 1027 cm-3 

Ans:     

9. For the n-channel MOSFET shown in the figure, threshold voltage Vth = 2 volts. The drain current ID of the MOSFET is 4 mA when the drain resistance RD is 1 kΩ. If the value of RD is increased to 4 kΩ, then the drain current ID will become:

ED9.PNG

  1. 2.8 mA
  2. 2.0 mA
  3. 1.4 mA
  4. 1.0 mA

Ans:     

10. Identify the sequence of semiconductors in ascending order of their band gap

  1. Si, Ge, GaP, GaAs
  2. Ge, Si, GaP, GaAs
  3. Ge, Si, GaAs, GaP
  4. Si, Ge, GaAs, GaP

Ans:     

11. When the gate to source voltage of a FET changes from - 5.2 volts to - 5 volts, the corresponding drain current changes from 1 mA to 1.3 mA, the transconductance is ___(in µ mho)

  1. 29
  2. 510
  3. 1500
  4. 1620

Ans:     

12. The energy band gap of the semiconductors silicon, germanium, Gallium Arsenide and silicon carbide are ……. in eV respectively.

  1. 3.3, 1.12, 0.72, 1.43
  2. 3.3, 1.12, 1.43, 0.72
  3. 1.12, 0.72, 1.43,3.3
  4. 1.12, 1.43, 3.3, 0.72

Ans:     

13.


ANALOG CIRCUITS

1. The gain of the amplifier falls at high frequencies, due to the

  1. Internal capacitances of the devices
  2. Skin effect
  3. Coupling capacitor at the input
  4. Coupling capacitor at the output

Ans:     

2. In the circuit shown below, the base current is _____ µA.

AC2.PNG

  1. 2.55
  2. 5.4
  3. 2.66
  4. 3.6

Ans:     

3. In the circuit shown in the figure, if input voltage Vi is 0.2 volt, then the output voltage Vo is______

AE.PNG

  1. 6 volts
  2. - 6 volts
  3. 8 volts
  4. -8 volts

Ans:     

4.  For a transistor inverter shown below, if ICsat is 10 mA, the value of RB and RC are

AC4.PNG

  1. 150 Ω and 1 kΩ
  2. 150 kΩ and 100 kΩ
  3. 155 kΩ and 1 kΩ
  4. 155 kΩ and 10 kΩ

Ans:     

5. The circuit shown below is a

AC5.PNG

  1. Free running oscillator
  2. Monostable multivibrator
  3. Comparator
  4. Schmitt trigger

Ans:     

6. If the emitter diffusion capacitance and transconductance of a transistor at high frequencies are 100 pF and 50 mA/V respectively, then the frequency at which the short circuit common emitter current gain attains unit magnitude is

  1. 1.25 MHz
  2. 79.57 MHz
  3. 55.28 MHz
  4. 7.23 MHz

Ans:     

7. A JFET has got the following specifications: VGS(OFF) = -2 volts, IDSS = 4 mA. When the applied VGS is one fourth of the VGS(OFF) to the JFET, then the drain current of the device would be

  1. 2.25 mA
  2. 4 mA
  3. 0.25 mA
  4. 1 mA

Ans:     

8. A voltage divider bias circuit uses n-channel JFET with VDD = 25 volts and Rs = 2.25  kΩ. To have minimum VDS = 10 volts and IDmax = 3 mA, the value of the drain resistance will be___

  1. 1.2 kΩ
  2. 3.9 kΩ
  3. 2.75 kΩ
  4. 270 Ω

Ans:     

9. In RC phase shift oscillator circuit using BJT, _____ feedback is employed.

  1. Voltage series
  2. Voltage shunt
  3. Current series
  4. Current shunt

Ans:     

10. The output voltage of the circuit shown below is

AE3.PNG

  1. - 10 V
  2. 5 V
  3. - 5 V
  4. 0.5 V

Ans:     

11. The differential gain of OP-AMP is 4000 and CMRR is 150. Its output voltage, when the two input voltages are 200 µV and 160 µV respectively will be

  1. 16 V
  2. 76 mV
  3. 64 mV
  4. 164.8 mV

Ans:     

12.


DIGITAL CIRCUITS

 1. In the given logic expression, A(A + B’C’ + C’) + B’(C’ + A’ +BC) + (A + B’C + AC’) = 1,  

     if C = A’ Then

  1. A + B’ = 1
  2. A’ + B = 1
  3. A + B = 1
  4. A = 1

Ans:      a

2. In a positive edge triggered JK flip-flop, the present state Qn is set to HIGH(1). If the inputs J = A and K = B, then the next state Qn+1 will  be

  1. A + B
  2. A’
  3. B’
  4. A

Ans:     

3.  The maximum positive and negative numbers which can be represented in 2’s complement form using n-bits are

  1. +(2n-1 - 1), -(2n-1 - 1)
  2. +(2n-1 - 1), - 2n-1 
  3. +2n-1 , - 2n-1 
  4. None

Ans:     

4. The following state diagram belongs to

DE4.PNG

  1. JK flip flop
  2. RS flip flop
  3. T flip flop
  4. D flip flop

Ans:     

5. Wired AND connection in ___

  1. TTL gates with active pull up
  2. TTL gates with open collector
  3. TTL gates without active pull up and with open collector
  4. All of the above

Ans:     

6.  The circuit shown in the figure is equivalent to

DE6.PNG

  1. OR gate
  2. Ex-OR gate
  3. NAND gate
  4. AND gate

Ans:     

7. If the input to T flip-flop is 100 Hz signal, the final output frequency of the three T flip-flops that are connected in cascade is

  1. 1000 Hz
  2. 500 Hz
  3. 333 Hz
  4. 12. 5 Hz

Ans:     

8.


NETWORKS

1. The voltage across 5 A current source in the given circuit is 

NT1.PNG

  1. 15 volts
  2. 25 volts
  3. 17.5 volts
  4. 20 volts

Ans:     

2. The current i(t) through a 10 Ω resistor in series with an inductance is given by i(t) = 3 + 4 sin(100t+45o) + 4 sin(300t+60o) amperes. The rms value of the current and the power dissipated in the circuit are

  1. 5 A, 250 W
  2. 10A, 350 W
  3. 40A, 410 W
  4. 11A, 250 W

Ans:     

3. An ideal voltage source and current sources are connected in parallel. This circuit has

  1. A Thevenin equivalent but not Norton’s equivalent
  2. Both Thevenin and Norton’s  equivalent
  3. Neither Thevenin nor Norton’s  equivalent
  4. A Norton’s equivalent but not Thevenin equivalent

Ans:     

4. A transient current in a network is i(t) = 2e-t - e-5t for t≥0. The pole-zero configuration of I(s) is

  1. Poles: 2, -1 and Zeros: -1, -5
  2. Poles: -1, -5 and Zeros: -9
  3. Poles: 1, 5 and Zeros:  9
  4. Poles: 2, -1 and Zeros: 1, 5

Ans:     

5. The given function F(s) = (s+1)(s+3)/s(s+2) represents an 

  1. RC impedance
  2. RL admittance
  3. RC impedance and an RL admittance
  4. RC admittance

Ans:     

6. When a source is delivering maximum power to a load, the efficiency of the circuit

  1. Depends on the circuit parameters
  2. Is always 75%
  3. Is always 50%
  4. Is always 100%

Ans:     

7. For a series RLC circuit, the power factor at the lowest half power frequency is

  1. 1.0
  2. 0.5
  3. 0.707 lagging
  4. 0.707 leading

Ans:     

8. A series RLC circuit has a resonant frequency of 1 kHz and a quality factor Q=100. If each of the R, L and C is doubled from their original values, the new Q of the circuit is

  1. 25
  2. 100
  3. 200
  4. 50

Ans:     

9. An inductance and a capacitance are connected in series. If a unit step voltage is applied across the combination, then the initial and final currents in the circuit will be

  1. ∞, ∞
  2. 0, 0
  3. 0, ∞
  4. ∞, 0

Ans:     

10. The network function F(s) = (s+2) / (s+1)(s+3) represents an

  1. RL impedance
  2. RC impedance
  3. RC admittance and an RL impedance
  4. RC impedance and an RL admittance

Ans:     

11. If B is the number of branches and N is the number of nodes in a connected graph, the number of links corresponding to any tree of the graph is

  1. N - B - 1
  2. B - N + 1
  3. B - N - 1
  4. N + 1 - B

Ans:     

12. For the circuit shown, find the frequency at which this circuit acts as an ideal current source with respect to terminals A and B?

NT12.PNG

  1. 1 rad/sec
  2. 0
  3. 16 rad/sec
  4. 4 rad/sec

Ans:     

13. The power dissipation in the resistor R4 of the following circuit will be_____ (in Watts)

NT13.PNG

  1. 10
  2. 15
  3. 20
  4. 100

Ans:     

14. A function f(t) is given as e-⍺t cos𝜔t. Its pole location in S-plane will be

NT14.PNG

Ans:     

15. Match the following lists :

NT15.PNG

  1. a - ii, b - i, c - iv, d - iii
  2. a - ii, b - i, c - iii, d - iv
  3. a - i, b - ii, c - iii, d - iv
  4. a - i, b - ii, c - iv, d - iii

Ans:     

16. With the signal generator frequency of a Q-meter set to 1.25 MHz, the Q of a coil is measured as 98, when capacitance C = 147 pF. Then the coil inductance and resistance would be

  1. 112 nH, 12 Ω
  2. 982 nH, 10 Ω
  3. 110 µH, 8.8 Ω
  4. 320 µH, 6.2 Ω

Ans:     

17. A pulse waveform with a 3.3 kΩ source resistance is to be displayed on an oscilloscope with an input capacitance of 15 pF. The rise time of the pulse shown on the scope is measured as

  1. 49.5 ns
  2. 54.45 ns
  3. 113.85 ns
  4. 109.0 ns

Ans:     

18. Three equal resistances of 3 ohm are connected in star. What is the resistance of one arm in equivalent delta?

  1. 1 ohm
  2. 3 ohm
  3. 9 ohm
  4. 27 ohm

Ans:     

19. In a series RLC circuit, if C is increased what happens to resonant frequency ?

  1. Increases
  2. Decreases
  3. Remains same
  4. Depends upon the value of R

Ans:     

20. In an RLC network, when all are connected in parallel, the driving point impedance of the network is given by A(s) = 0.2s / [s2 + 0.1s + 2]. The component values L, R and C in henry, ohms and farads respectively

  1. 5, 0.5, 0.1
  2. 0.1, 0.5, 5
  3. 5, 2, 0.1
  4. 0.1, 2, 5

Ans:     

21.  The maximum percentage error in the sum of two voltage measurements when V1 = 100±1% and V2 = 80±5% is

  1. 180±6.0%
  2. 180±4.0%
  3. 180±2.8%
  4. 180±3.6%

Ans:     

22.


CONTROL SYSTEMS

1.  The transfer function of a system Z(s) = V(s)/I(s) = s/(s+3). The system is at rest for t<0. What will be the value of v(t) for t≥0, if i(t) = 3 u(t) is applied, where u(t) is a unit step function.

  1. 2 e-3t
  2. 4e-t
  3. e-t
  4. 3e-3t

Ans:     

2.  The laplace transform of the function i(t) is I(s) = 10(s+4)/s(s+1)(s2+4s+5). Its final value will be

  1. 5
  2. 1.25
  3. 4

Ans:     

3. The transfer function of a phase lead controller is (1 + 3Ts)/(1+Ts), the maximum value of phase provided by this controller is

  1. 45o
  2. 60o
  3. 90o
  4. 30o 

Ans:     

4. The characteristic polynomial of a system q(s) = 2s5 + s4 + 4s3 + 2s2 +2s + 1. The system is

  1. Unstable
  2. Marginally stable
  3. Stable
  4. Oscillatory

Ans:     

5. The system mode described by the following equation is 

CS1.PNG

  1. Observable but not controllable
  2. Controllable but not observable
  3. Controllable and observable
  4. Neither controllable nor observable

Ans:     

6. If s3 + 3s2 + 4s + A = 0, then all the roots of this equation are in the left half plane provided that

  1. 0 < A < 12
  2. -3 < A < 4
  3. A > 12
  4. 5 < A < 12

Ans:     

7. The gain margin of the system with open loop transfer function G(s)H(s) = 2(1 + s)/s2 is

  1. 1
  2. 0
  3. -∞

Ans:     

8. The Nyquist plot of a loop transfer function G(j⍵)H(j⍵) of a system encloses the (-1, j0) point, the gain margin of the system is

  1. Greater than zero
  2. Zero
  3. Less than zero
  4. Infinity

Ans:     

9. For the circuits shown, arrange them in terms of decreasing number of total number of poles and zeros.

CS9.PNG

  1. a, b, c
  2. a, c, b
  3. b, a , c
  4. c, b, a

Ans:     

10. The addition of a pole to a forward path transfer function of a closed loop system, generally has the effect of

  1. Decreasing the maximum overshoot
  2. Increasing the maximum overshoot
  3. Maintaining the maximum overshoot
  4. Does not affect the maximum overshoot

Ans:     

11. The pole-zero configuration of a PI controller is represented by

CS11.PNG

Ans:     

12. The open loop transfer function of a system is G(s)H(s) = 10s/s(1+0.25s). The frequency in rad/sec at which the Nyquist plot intersects with -ve real axis is

  1. 2.5
  2. Infinity
  3. Zero
  4. 4

Ans:     

13. A stable linear time invariant system has a transfer function, H(s) = 1 / [s2 + s - 6]. To make this system casual, it needs to be cascaded with another LTI system having a transfer function H1(s). A correct choice for H1(s) is

  1. S + 3
  2. S - 2
  3. S - 6
  4. S + 1

Ans:     

14. In a bode magnitude plot, which one of the following slopes would be exhibited at high frequencies by a 4th order all pole system?

  1. - 80 dB/decade
  2. - 40 dB/decade
  3. + 40 dB/decade
  4. + 80 dB/decade

Ans:     

15. For the second order closed loop system shown in figure, the natural frequency (in rad/sec) is

CS15.PNG

  1. 16
  2. 4
  3. 2
  4. 1

Ans:     

16. An integral controller has a value of K````````````````````````````````````````` = 0.1 per sec. What will be the output after t =1 sec, if there is a sudden change to a constant error of 20%?

  1. 4%
  2. 2%
  3. 8%
  4. 20%

Ans:     

17. Given the system transfer function, G(s) = Ke-0.2s / [s(s+2)(s+8)], the corner frequencies in rad/sec are

  1. 0.2, 0.6
  2. 1, 4
  3. 3, 7
  4. 2, 8

Ans:     

18.


SIGNALS & SYSTEMS

  1. X is a random variable with variance 𝞂x2. The variance of (X+a), where a is a constant is
  1. (𝞂x2+a2)
  2. 𝞂x2
  3. (𝞂x+a)2
  4. (𝞂x2 - a2)

Ans:     

2. Two random processes X and Y are such that RXY(t1,t2) = 0 for all t1 and t2, and further one of them has zero mean. The processes are

  1. Statistically independent
  2. Orthogonal but not uncorrelated
  3. Uncorrelated but not orthogonal
  4. Orthogonal and uncorrelated

Ans:     

3. Mutual information I(X:Y) between two discrete random variables X and Y is given by

  1. H(Y) - H(X|Y)
  2. H(X) - H(Y|X)
  3. H(X) + H(Y) - H(X,Y)
  4. H(X) + H(Y) + H(X,Y)

Ans:     

4. It is possible to compute the cross correlation Rxy(𝒯) between two signals x(t) and y(t) directly from their convolution, provided

  1. y(t) has odd symmetry
  2. x(t) has odd symmetry
  3. x(t) has even symmetry
  4. y(t) has even symmetry

Ans:     

5. A random variable is uniformly distributed between 3 and 6. Its variance is

  1. 0.5
  2. 0.25
  3. 0.75
  4. 1

Ans:     

6. Given x(t) = 3 cos2250𝜋t. This signal is sampled at regular intervals of T seconds. The maximum value of T for which x(t) may be recovered from the sampled version without any distortion, is equal to

  1. 4 ms
  2. 2 ms
  3. 1 ms
  4. 0.5 ms

Ans:     

7. The signal e-tu(t) is applied as input to an L-section RC lowpass filter with time constant equal to 1. The energy spectral density at the output of the filter at the 3 dB cutoff frequency of the filter is

  1. 0.25
  2. 0.5
  3. 1
  4. 1.5

Ans:     

8. Two LTI systems with impulse responses h1(t) and h2(t) are connected in series (cascade), the impulse response of the overall system is

  1. h1(t) * h2(t)
  2. (h1(t).h2(t))/(h1(t) + h2(t))
  3. h1(t) + h2(t)
  4. h1(t) . h2(t)

Ans:     

9. Two parallel connected discrete time systems with impulse responses h1(n) and h2(n) can be replaced by a single equivalent discrete time system with impulse response,

  1. h1(n) - h2(n)
  2. h1(n) + h2(n)
  3. h1(n) * h2(n)
  4. h1(n) * [h1(n) + h2(n)]

Ans:     

10. The fourier series of a periodic signal x(t) with period T will not converge if

  1. x(t) is not continuous at all points
  2. x(t) has more than one maxima in one period T
  3. |x(t)| is not finite at all values of t
  4. x(t) is not a band limited signal

Ans:     

11. Which of the following signal is an example for deterministic signal?

  1. Step
  2. Ramp
  3. Exponential
  4. All of the above

Ans:     

12. If a signal is folded about the origin in time, then its

  1. Magnitude spectrum undergoes change in sign
  2. Phase spectrum undergoes change in sign
  3. Magnitude remains unchanged
  4. Both b and c

Ans:     

13. The correct expression of the following triangular wave is:

SS13.PNG

Ans:     

14. Which of the following cannot be the Fourier series expansion of a periodic signal?

  1. x(t) = 2 cost + 3 cos 3t
  2. x(t) = 2 cos𝜋t + 7 cos t
  3. x(t) = cos t + 0.5
  4. x(t) = 2 cos 1.5𝜋t + sin 3.5𝜋t

Ans:     

15.

16. The average value of a periodic trapezoidal waveform is given by:  

SS17.PNG

Ans:     

17. The maximum and minimum values of autocorrelation function of a binary signal 1,1, 1, -1, -1, 1, -1 are

  1. 14, 7
  2. 7, -1
  3. 14, 2
  4. 7, 1

Ans:     

18. The Z-transform of a sequence u[n] - u[n-2] is

  1. 1 + z
  2. 1 - z-1
  3. z/(z-1)
  4. 1 + z-1

Ans:     

19.


COMMUNICATION  SYSTEMS

1. One of the following bandpass digital modulation schemes is not suitable for transmission over nonlinear bandpass channels:

  1. PSK
  2. ASK
  3. FSK
  4. QFSK

Ans:     

2. An amplitude modulated wave is given by

Xc(t) = 10 cos 1200𝜋t + 40 cos1400𝜋t + 10 cos1600𝜋t. The modulating signal frequency and modulation index are

  1. 200 Hz, 0.25
  2. 400 Hz, 0.25
  3. 200 Hz, 0.5
  4. 400 Hz, 0.5

Ans:     

3. When sinusoidally modulated, the rms value of the current in the antenna of an AM transmitter increases 15% over its unmodulated value. The modulation index is

  1. 0.5
  2. 0.8
  3. 0.6
  4. 0.707

Ans:     

4. For a frequency modulated signal, the modulation index is doubled. The average power of the modulated signal is

  1. Quadrupled
  2. Doubled
  3. Unaltered
  4. None of these

Ans:     

5. Pre-emphasis is for

  1. Boosting up of the low frequency components of the message signal after detection in the receiver
  2. Boosting up of the high frequency components of the message signal at the transmitter before modulation
  3. Boosting up of the high frequency components of the message signal after detection in the receiver
  4. Boosting up of the low frequency components of the message signal at the transmitter before modulation

Ans:     

6. A superheterodyne AM broadcast receiver has an IF of 455 kHz. If it is tuned to a frequency of 700 kHz, the image frequency is

  1. 245 kHz
  2. 1155 kHz
  3. 1610 kHz
  4. 210 kHz

Ans:     

7. A message signal with its amplitude uniformly distributed between -2 volts and +2 volts is transmitted by a 4 bit binary PCM system. The (SNR)q is equal to

  1. 512
  2. 1024
  3. 256
  4. 768

Ans:     

8. The occurrence of double spotting indicates that

  1. Image rejection capability of the receiver is inadequate
  2. The selectivity is poor
  3. The IF is too high
  4. The local oscillator frequency is less than that of the incoming signal.

Ans:     

9.  In amplitude modulation, _____ of total transmitted power is used for carrying message signal under best conditions.

  1. 25%
  2. 33%
  3. 50%
  4. 78%

Ans:     

10. A PCM system uses Nyquist sampler, a uniform quantizer followed by a 5 bit binary encoder. The bit rate is 50 Mbps. the maximum message bandwidth for which the system operates satisfactorily is

  1. 3 kHz
  2. 2.5 kHz
  3. 2 kHz
  4. 5 kHz

Ans:     

11.


EMTL

  1. Wave propagation in +Z direction, E is given as Ex = 2 cost and Ey = 2 cos(t+90o). The wave is
  1. Left circularly polarized
  2. Right circularly polarized
  3. Linearly polarized
  4. Elliptically polarized

Ans:     

2. The input impedance of short circuited lossless line of length less than a quarter wavelength is ________

  1. Purely capacitive
  2. Purely inductive
  3. Purely resistive
  4. Complex form

Ans:     

3. A 50 Ω loss less transmission line is terminated in 100 Ω load and is excited by a 30 MHz source of internal resistance of 50 Ω . What  should be the length of the transmission line for maximum power transfer _______

  1. 2.5 m
  2. 1.25 m
  3. 5 m
  4. 10 m

Ans:     

4. The electric field measured in the far field of an antenna at a distance of 50 m is 1 V/m. The average power density at a distance of 500 m from the antenna is

  1. 10 µW/m2 
  2. 0.1 µW/m2 
  3. 26.6 µW/m2 
  4. 13.3 µW/m2 

Ans:     

5. For a lossy transmission line, the characteristic impedance does not depend on

  1. The operating frequency of the line
  2. The length of the line
  3. The load terminating the line
  4. Both b and c

Ans:     

6. At microwave frequencies, we prefer waveguides to transmission lines for transporting EM energy because of all the following except that

  1. Transmission lines are larger than waveguides
  2. Waveguides have larger bandwidths and lower signal attenuation
  3. Losses in transmission lines are prohibitively large
  4. Transmission lines support only TEM mode

Ans:     

7. When the electric field is at its maximum value, the magnetic energy of the cavity is

  1. At ½ of its maximum value
  2. At √2 of its maximum value
  3. At its maximum value
  4. Zero

Ans:     

8. The divergence of vector is

EMTL5.PNG

  1. Rotational
  2. Irrotational
  3. Solenoidal
  4. Both b and c

Ans:     

9. The value of electric field at a distance of 1m from an infinite line charge density of 1 C/m is

  1. 𝜀o/2𝜋
  2. 1/2𝜋𝜀o
  3. 2𝜋𝜀o
  4. 2𝜋/𝜀o

Ans:     

10. A line terminated in its characteristic impedance has SWR of______

  1. Zero
  2. Unity
  3. Infinity
  4. Two

Ans:     

11. Which one of the following modes has the highest cut-off wavelength in a rectangular waveguide?

  1. TM01
  2. TE01
  3. TE10
  4. TM11

Ans:     

12. If in a rectangular waveguide for which a = 2b, the cutoff frequency for TE02 mode is 12 GHz, the cutoff frequency for TM11 mode is

  1. 12 GHz
  2. 3√5 GHz
  3. 3 GHz
  4. 6√5 GHz

Ans:     

13. An electric potential field is produced by point charges 1 µC and 4 µC located at (-2, 1, 5) and (1,3,-1), respectively. The energy stored in the field is

  1. 2.57 mJ
  2. 5.14 mJ
  3. 10.28 mJ
  4. None of these

Ans:     

14. A plane wave propagates in water (Ɛr = 81). If the peak electric field is 20𝜋 V/m, then the peak magnetic field intensity will be

  1. 10 𝜋 A/m
  2. 5 A/m
  3. 1.5 A/m
  4. 20 A/m

Ans:     

15. A wave is propagated in a parallel-plane waveguide. If the frequency is 6 GHz and the plane separation is 3 cm then the cut-off wavelength for the dominant mode will be:

  1. 3 cm
  2. 6 cm
  3. 12 cm
  4. 9 cm

Ans:     

16. A high frequency signal is frequency modulated by n number of modulating signals. The ideal number of sidebands in the modulated signals will be

  1. n
  2. 2n
  3. 4n
  4. Infinite

Ans:     

17. For a quarter wave ideal transmission line of characteristic impedance of 50 Ω and load impedance of 100 Ω, the input impedance of line will be:

  1. 50 Ω
  2. 25 Ω
  3. 100 Ω
  4. 175 Ω

Ans:     

18. A TEM wave impinges obliquely on a dielectric - dielectric boundary with ɛr1 = 2 of one medium and ɛr2 = 1 of another medium. The value of angle of incidence for total internal reflection is : (in degrees)

  1. 45
  2. 30
  3. 60
  4. 75

Ans:     

19. Match the following:

EMTL.PNG

  1. a-i, b-ii, c- iii, d-iv
  2. a-iv, b-ii, c- iii, d-i
  3. a-iV, b-iii, c- ii, d-i
  4. a-i, b-iii, c- ii, d-iv

Ans:     

20.


MICROPROCESSOR

  1. The contents of the accumulator after the execution of the follwoing instruction will be:

        MVI   A, A7H

ORA   A

RLC

  1. CFH
  2. 4FH
  3. 4EH
  4. CEH

Ans:     

2. The contents of Accumulator register after execution of the following 8085 program is

         MVI  A, 55H

        MVI  C, 25H

        ADD  C

        DAA

  1. 22H
  2. 50H
  3. 80H
  4. 7AH

Ans:     

3. What is the duration of the bus-cycle in an 8086 microprocessor, if the clock frequency is 12 kHz without any wait states?

  1. 83 ns
  2. 581 ns
  3. 332 ns
  4. 249 ns

Ans:     

4.