Question

What happens when a positively charged glass rod is made to touch the metal knob of an electroscope?

• A. The leaves of the electroscope become negatively charged.
• B. The leaves of the electroscope would repel each other.
• C. The leaves of the electroscope become positively charged.
• D. The leaves of the electroscope would attract each other.

Answer 1

Answer: (B), (C)

The correct options are
B The leaves of the electroscope would repel each other.
C The leaves of the electroscope become positively charged.

When a positively charged glass rod touches the metal knob of a gold leaf electroscope, the electrons travel from the leaves to the metal rod. As a result, the leaves become positively charged. Since the charge on both the leaves is the same, they are repelled away from each other, and hence, spread apart.