Tag: electric charges and fields

Questions Related to electric charges and fields

During electrification by friction

physics electric charges and fields explaining static electricity charging by induction static electricity

  1. Proton are transferred from one body to another body

  2. Neutrons are transferred from one body to another body

  3. Electrons are transferred from one body to another body

  4. None

Show answer
Correct Option: C
Explanation:

When a body is rubbed over another,transfer of electrons from one body to another. Thus one body acquires a net positive charge and the other acquires net negative charge.proton and neutron are packed in the nucleus thus they cannot move.

example - When a glass rod is rubbed with a silk cloth some electrons from the glass attach themselves to the silk. Consequently, the glass becomes positively charged and the silk negatively charged. Likewise when ebonite is rubbed with fur electrons are transferred from fur to ebonite, thus making the ebonite negative and the fur positive.

Option C is correct.

An ebonite rod rubbed with fur and a glass rod rubbed with silk cloth are brought nearer to each other. Then

physics static electricity explaining static electricity charging by induction electric charges and fields

  1. they will attract each other

  2. they will repel each other

  3. nothing will happen to them

  4. they will get heated up

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Correct Option: A
Explanation:

When an ebonite rod is rubbed with fur, the ebonite rod gets negatively charged and the fur becomes positively charged. Whereas when a glass rod is rubbed with silk cloth, the glass rod becomes positively charged and the silk cloth becomes negatively charged.

Now as we know that unlike charges attract each other, thus the glass rod and the ebonite rod will attract each other as they have opposite charges.

Which of the following statement is NOT true?

physics static electricity explaining static electricity charging by induction electric charges and fields

  1. Lightning and spark from woolen clothing are essentially the same phenomena.

  2. When you rub a plastic scale on your dry hair, it acquires a charge.

  3. Charge acquired by a glass rod when it is rubbed with silk is called as negative charge.

  4. Static charges are called so, because they do not move by themselves

Show answer
Correct Option: C
Explanation:

When a glass rod is rubbed with silk then it gets net positive charge whereas silk gets negatively charges by electron transfer through friction.When a glass rod is rubbed with silk, it acquires a positive charge whereas silk acquires a negative charge. So, statement is not True.

The electric charge developed on glass rod rubbed with silk cloth is different from the charge developed on ebonite rod rubbed with fur.

physics static electricity explaining static electricity charging by induction electric charges and fields

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

When glass rod is rubbed with silk cloth, it acquires positive charge.
But when ebonite rod is rubbed with fur, the rod gets negatively charged.
So, charge developed on glass rod rubbed with silk is different from charge developed on ebonite rod rubbed with fur. Hence this statement is true.

The electricity developed on objects, when they are rubbed with each other is called:

physics static electricity explaining static electricity charging by induction electric charges and fields

  1. Frictional potential

  2. Frictional electricity

  3. Static electricity

  4. Static potential

Show answer
Correct Option: B
Explanation:

The electricity developed on the objects when they are rubbed with each other is called Frictional electricity. On rubbing two objects, both materials get electrified due to friction produced while rubbing them. One of the body acquires negative charge and other acquires positive charge.

A woolen cloth when rubbed against plastic object acquires ______ charge.

physics static electricity explaining static electricity charging by induction electric charges and fields

  1. Sometimes positive and sometimes negative

  2. Negative

  3. Positive

  4. None of the these

Show answer
Correct Option: C
Explanation:

When woolen cloth is rubbed against the plastic, both wood and plastic get electrified due to friction produced while rubbing. So, plastic has greater electron affinity (ability to attract electrons) as compared to wool, therefore, plastic acquires negative charge and wool acquires positive charge.

A glass rod when rubbed with silk cloth, acquires a charge of $1.6\times 10^{-11}C$, then the charge on silk cloth will be:

physics static electricity explaining static electricity charging by induction electric charges and fields

  1. $-3.2\times 10^{-11}C$

  2. $-2.4\times 10^{-13}C$

  3. $-1.6\times 10^{-13}C$

  4. $-1.6\times 10^{-11}C$

Show answer
Correct Option: D
Explanation:

When glass rod is rubbed with silk, electrons move from rod to silk.


Since silk gets electrons it becomes negatively charged and the number of electrons gained by silk is same as that lost by rod.

Hence magnitude of charge on silk is same as that on rod.

Hence charge on silk$=-1.6\times 10^{-11}C$ 

Answer-(D)

When a polythene piece is rubbed with wool, it acquires negative charge. 

physics static electricity explaining static electricity charging by induction electric charges and fields

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

When a polythene piece is rubbed with wool, both gets electrified due to charging by friction. Since polythene has greater electron affinity (ability to attract electrons) as compared to wool. So, polythene piece attracts electron and acquires negative charge and wool acquires positive charge.

Which statement best explains why a rubber rod becomes negatively charged when rubbed with fur?

physics static electricity explaining static electricity charging by induction electric charges and fields

  1. The rubber that the rod is made of is a better insulator than fur.

  2. The fur is a better insulator than the rubber.

  3. Molecules in the rubber rod have a stronger attraction for electrons than the molecules in the fur.

  4. Molecules in the fur have a stronger attraction for electrons than the molecules in the rubber rod.

Show answer
Correct Option: C
Explanation:

During charging by rubbing (or by friction) process, the material that becomes negatively charged does so because it likes electrons more than the material with which it is rubbed. It means molecules in rubber rod have a stronger attraction for electrons than the molecules in the fur. 

During a physics lab, a plastic strip was rubbed with cotton and became positively charged. The correct explanation for why the plastic strip becomes positively charged is that

physics static electricity explaining static electricity charging by induction electric charges and fields

  1. the plastic strip acquired extra protons from the cotton.

  2. the plastic strip acquired extra protons during the charging process.

  3. protons were created as the result of the charging process.

  4. the plastic strip lost electrons to the cotton during the charging process.

Show answer
Correct Option: D
Explanation:

Plastic strip when rubbed with cotton got charged due to charging by friction.
The plastic strip and cotton acquires opposite charges. This is because plastic strip acquires positive charges and loses electrons to cotton during the process, and therefore cotton acquires the negative charge.