Question

An ebonite rod held in hand can be charged by rubbing with flannel but a copper rod cannot be charged like this. Why?

Answer 1

In this question, we need to comment on the given statement. For this we will use the concept of the conductor and inductors. An ebonite rod is a bad conductor of electricity. On the other hand, a copper rod is a good conductor of electricity.

Complete step by step answer:
When an ebonite rod is held in hand, it can be charged by rubbing with a flannel. This happens because the ebonite rod is a bad conductor of electricity. Due to this, the charges stay on the rod.
On the other hand, when a copper rod is held in hand, it cannot be charged by rubbing with a flannel. This happens because copper rod is a good conductor of electricity. Therefore, the charges produced can flow through it.
Our human body is also a good conductor of electricity. So, similar to the copper rod, the charges can flow through our body too.
Due to this, when the charges are produced by rubbing the copper rod with a flannel, they flow the rod first followed by the hand. They flow through the body to the ground.
Hence, the copper rod cannot be charged.
Therefore, an ebonite rod held in hand can be charged by rubbing it with a flannel but a copper rod cannot be charged like this.

Note:
Students get confused between which one is a good conductor and which one is the bad conductor of electricity.
They tend to mention that the charges flow through bad conductors and the charges stay on the good conductors which is wrong.