Chapter 16, Problem 1Q

If you charge a pocket comb by rubbing it with a silk scarf, how can you determine if the comb is positively or negatively charged?

To determine

If we charge a pocket comb by rubbing it with a silk scarf, how can we determine whether the comb is positively or negatively charged?

Answer to Problem 1Q

Solution:

Bring the charged comb close to the ruler. If the ruler is attracted by the comb, then the comb is positively charged. And if the ruler is repelled by the comb, then the comb is negatively charged.

Explanation of Solution

In order to determine whether the comb is positively or negatively charged, a plastic ruler is suspended by a thread and then rubbed with a cloth, and then as we know that the ruler will acquire negative charge from cloth. Now bring the charged comb close to the ruler. If the ruler is attracted to the comb, then the comb is positively charged. And if the ruler is repelled by the comb, then the comb is negatively charged.