Chapter 21, 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

The method to determine whether the comb is positive or negative.

Answer to Problem 1Q

By using an electroscope, the charge of a pocket comb can be determined.

Explanation of Solution

A pocket comb can be charged by rubbing it with a silk material. To determine the charge of the comb, electroscope can be used. Electroscope is made of glass.

When a glass is rubbed with silk, it will get positively charged. Bring the charged comb near to the electroscope. When the leaves of the electroscope moves away from each other, then the comb are positively charged as same charges repels. If the leaves come closer, then the comb is negatively charged. Therefore, by using an electroscope, the charge of a pocket comb can be determined.