Question

Which of the following cannot be charged easily by friction?

• A. A plastic scale.
• B. A copper rod.
• C. An inflated balloon.
• D. A woolen cloth.

Answer 1

The correct option is B

A copper rod.

Friction

1. It is the resisting force that acts upon objects sliding or rolling over one another
2. They are necessary in some cases like walking without slipping, but it opposes motion.
3. Rubbing one thing against another produces friction.

Charging by friction

1. The transfer of electrons from one object to another by rubbing two objects together is called charging by friction.
2. In this case, due to friction, one body loses the electrons and the other body gains it resulting in the body losing electrons to become positively charged and the body gaining the electrons to become negatively charged.

The explanation of the correct answer

Option B

1. A copper rod is a conductor. So, it cannot be charged by friction.
2. In the case of conductors, when the electrons are transferred from one body to another due to the charging by friction, the electrons again transfer back to the body due to the conductive behavior of the rubbing bodies.
3. Thus, making it neutralize again.

Therefore, option B is correct.

The explanation of the incorrect answer

Option A

1. A plastic scale is an insulator and hence, it can be charged by friction by rubbing because the electrons don't get transferred back to the body due to the insulating behavior of the body.

Option C

1. An inflated balloon is an insulator and hence, it can be charged by friction by rubbing because the electrons don't get transferred back to the body due to the insulating behavior of the body.

Option D

1. Woolen cloths are all bad conductors, so they can be charged by friction by rubbing because the electrons don't get transferred back to the body due to the insulating behavior of the body.

Therefore, options A, C, and D are incorrect

Hence, option B is the correct answer.