• Learning Objectives
• Define static electricity and electrostatics.
• Describe that there are two types of charges and conventionally charge on electron is taken as negative and that on proton is taken as positive.
• Identify the unit of charge as coulomb and its notation as “C”
• Calculate the number of electrons or protons in a given charge using the value of elementary charge 1.6 × 10¹⁹ C

Keywords

• Electrostatics
• coulomb
• Elementary charge

ELECTRICITY AND MAGNETISM

• Starter activity
• https://wordwall.net/resource/10765699/parts-of-an-atom

ELECTRICITY AND MAGNETISM

• Identify the names of positive ,negative and neutral particle in the atom

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3 minutes

• Starter activity

ELECTRICITY AND MAGNETISM

• Protons are positively charged particles

• Electrons are negatively charged

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• Electrons are outside the nucleus

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• Find the ( net Charge )total charge of the atoms shown below

ELECTRICITY AND MAGNETISM

Atom A

Atom B

• The charge on a proton and electron are the same Protons and electrons have same amount charge, but Proton is Positive

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• Electron is negative

Net charge = number of protons – no of electrons

• Atom gets charged when it gain or loose electron

• Let’s investigate more about electric charges

ELECTRICITY AND MAGNETISM

Instructions

Go to the link

Select two balloons and identify what happens when both balloons have the same charge

https://phet.colorado.edu/sims/html/balloons-and-static-electricity/latest/balloons-and-static-electricity_en.html

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Complete the following questions after the virtual lab

• What are the charged particles present in an tom

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• Like charges ………. ( attract / repel)
• Unlike charges ………………….. ( attract / repel)

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5 minutes

SLO:

- The force between the charged objects.

Like charges:

Two objects with like charges always repel each other.

Unlike charges:

Unlike charges attract.

ELECTRICITY AND MAGNETISM

• Electrostatics ( Study of charges at rest )

The study of electric charges that can be collected and held in one place.

SLO:

- Identify the types of charges.

Types of charges:

• There are only two types of charge.
• Benjamin Franklin called them positive charges and negative charges.
• Materials have varying degrees of ability to acquire charge.
• Hard rubber and plastic have a tendency to become negatively charged.
• Glass and wool have a tendency to become positively charged.

Critical thinking: Why do materials vary the ability to acquire either positive or negative charge?

SLO:

- Describe why the atoms are neutral???

Microscopic view of electric charges:

• In 1897 J.J. Thomson discovered that all materials contain low-mass, negatively charged particles. These particles are called electrons.
• Between 1909 and 1911, Ernest Rutherford, discovered that the atom has a massive, positively charged nucleus surrounded by a cloud of orbiting electrons.
• Scientists know that atoms are normally neutral because the amount of negative charge exactly balances the amount of positive charge.

:Check your understanding

AFL:Check your understanding

• Learning Objectives
• Identify the unit of charge as coulomb and its notation as “C”
• Calculate the number of electrons or protons in a given charge using the value of elementary charge 1.6 × 10^-19 C

Keywords

• Electrostatics
• coulomb
• Elementary charge

ELECTRICITY AND MAGNETISM

• Conductors and insulators
• https://wordwall.net/resource/1738575/electrical-conductors-and-insulators

ELECTRICITY AND MAGNETISM

3 minutes

Extended activity

https://wordwall.net/resource/11095932/physics-static-electricity

Conductors and insulators

Insulators

• A material through which a charge will not move easily is called an electric insulator.
• Glass, dry wood, most plastics, cloth, and dry air are all good insulators.
• An insulator holds charges where they are placed.

Conductors

• A material that allows charges to move about easily is called an electric conductor.
• most metals are good conductors.
• Charge spreads out evenly on a conductor.

SLO: Comparing conductors and insulators

Why metals are good conductors?

• We know that most metals are good conductors. This is because at least one electron of each atom of a metal can be removed easily.
• Electrons are free to move in conductors

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Application of conductors

• Copper and Aluminium are both excellent conductors and are used commercially to carry electric charge. Some nonmetal materials also are good conductors. These include plasma, which consists of negative electrons and positive ions, and graphite.

SLO:

Describe the transfer of electrons

Transfer of electrons:

SLO:

Describe the transfer of electrons

Transfer of electrons:

• The outer electrons of an atom can be removed from the atom.

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• From a microscopic viewpoint, acquiring charge is a process of transferring electrons.

Only electrons can move in an atom.

SLO:

- Describe the transfer of electrons

Separation of charge:

If you rub two neutral objects together, each object can become charged.

For instance, when you rub rubber shoes on a wool rug, the energy from the rubbing removes outer electrons from atoms in the wool, and they transfer to the rubber shoe.

The extra electrons on the shoe result in a net negative charge on the shoe.

The electrons missing from the wool rug result in a net positive charge on the rug.

A net positive or negative charge means that electrons have been transferred.

• What happens to the mass of the substance when electrons are added to it ?
• What is the mass of an electron?
• What is the charge of an electron?

ELECTRICITY AND MAGNETISM

Use google and

Post the answers in the chat

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• Mass of an electron = 9.1093837015(28)×10−31 kg

ELECTRICITY AND MAGNETISM

• Charge of an electron =1.60217662 × 10^-19 coulombs

1.Matar transfer 189400 electrons from object A to object B

1. What is the net charge of object B now?
2. What happens to the mass of object B

• Charge of an electron

=1.60 × 10^-19 coulombs

Mass of an electron = 9.11×10−31 kg

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ELECTRICITY AND MAGNETISM

The charge on an object can be found by using the formula

• e =1.6 × 10^-19 coulombs
• n = Number of electrons

Calculate the number electrons transferred to a sphere if its net charge is

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= -4.096✖ 10^-16

• Conservation of electric charge
• How can you charge an object ?
• What is the net charge of the atom shown below

ELECTRICITY AND MAGNETISM

Atom A

Electric charge is conserved:

The combined total charge of the two objects remains the same. Charge is conserved, which is one way of saying we cannot create or destroy charge