Physics 2009 JAMB Past Questions - Question 39: If negative charges are induced rod is brought near the cap of the electroscope, the leaves will

Correct Answer

A

Explanation

When a negatively charged rod is brought near the cap of an electroscope, the leaves of the electroscope will diverge or spread apart. This happens because the negatively charged rod induces a temporary redistribution of charges in the electroscope.

Here's what occurs step by step:

1. The negatively charged rod is brought close to the cap of the electroscope.

2. Due to electrostatic induction, electrons in the electroscope's metal rod are repelled away from the cap. This leaves an excess of positive charges on the cap and a corresponding deficit of electrons in the metal rod.

3. Because like charges repel each other, the leaves of the electroscope, which are usually neutral, become charged with the same sign as the excess positive charges on the cap. In this case, they become positively charged.

4. Since the leaves now carry the same positive charge, they repel each other, causing them to spread apart.

So, when a negatively charged rod is brought near the cap of the electroscope, the leaves will diverge, indicating a positive charge on the leaves due to the induction process.