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

The explanation of the correct option (B):

1. Copper rod cannot be charged easily by friction because it is a conductor, only non-conducting material gets charged by friction.
2. Due to the friction between two object, electrons from one object gets transferred to the other one.
3. An object which loses electrons becomes positively charged and the other negatively charged.
4. Non-conducting materials are the only material that is charged easily by friction.

The explanation for the incorrect options (A), (C), and (D):

1. A plastic scale can be charged by rubbing it against the woolen cloth. Upon rubbing, the wool loses electrons and it causes the electrons to move from the wool to the scale's surface. The rubbed part of the scale will be negatively charged and woolen cloth positively charged.
2. An inflated balloon can also be charged by rubbing it against the woolen cloth.
3. Upon rubbing, the wool loses electrons and it causes the electrons to move from the wool to the balloon's surface. The rubbed part of the balloon will be negatively charged and the woolen cloth positively charged.

Therefore, option B is the correct answer.