Question

A comb run through one's hair attracts small bits of paper. What happens, if the hair is wet or if it is a rainy day?
A. The comb does not get charged and it will not attract small bits of paper.
B. The comb does not get charged but it will attract small bits of paper.
C. The comb does not get charged and it will attract small bits of paper.
D. The comb does get charged but it will not attract small bits of paper.

Answer 1

Hint: Comb gets electrically charged by friction when even through dry hair. It attracts small bits of paper because paper gets polarized in the presence if charged comb resulting in a net force of attraction.

Complete step by step answer:
When comb runs through dry hair, it attracts small bits of paper. This is because the comb gets charged by friction.
Comb gets electrically charged by friction.
Due to electric charge, paper gets polarized and it attracts small bits of paper.
The important thing required to create electric charge in the comb is friction. As friction increases, electric charge in the comb also increases.
But when the comb runs through wet hair no electric charge is produced because friction between hair and comb is reduced.
Due to absence of electric charge in comb it cannot polarize small bits of paper.
Hence comb cannot attract small bits of paper.

Hence we can say that the comb does not get charged and it will not attract small bits of paper.

Note:If the hair is wet, or if it is a rainy day, friction between the hair and the comb reduces. The comb does not get charged, and it will not attract small bits of paper. The important thing required to create electric charge in the comb is friction. As friction increases, electric charge in the comb also increases. Normal dry hairs create enough friction to charge the comb but that will not happen in case of wet hairs. The charge attracts small bits of paper.