Question

An electroscope is a device that detects charge on objects that touch it or are brought near it. John rubs a piece of cotton fabric on a plastic rod and then touches the rod to the electroscope.

What methods of charging does John use?

John charges the rod through induction, then charges the electroscope through friction.
John charges the rod through conduction, then charges the electroscope through induction.
John charges the rod through friction, then charges the electroscope through induction.
John charges the rod through friction, then charges the electroscope through conduction.

Answer 1

In this scenario, John first rubs a piece of cotton fabric on a plastic rod. This process is known as charging by **friction**. The rubbing of the fabric on the rod transfers electrons, causing the rod to become charged.

Next, when John touches the charged rod to the electroscope, he is transferring charge directly from the rod to the electroscope. This process is known as charging by **conduction**, since there is direct contact between the charged rod and the electroscope.

So, the correct interpretation of the methods of charging used is:

**John charges the rod through friction, then charges the electroscope through conduction.**