When people use plastic combs on their hair, the combs become negatively charged. which statements about this situation are true?

the comb loses electrons.
the comb gains electrons.
the hair loses electrons.
the hair gains protons.
the hair loses protons.

those above are the choices

The correct answer is "The comb gains electrons".

Explanation:

A static charge is induced by rubbing the two surfaces of the material. These materials are not a good conductor of electricity.

The electrons are transferred from one material to the other.

A static charge is induced on a material when the material loses electrons due to friction.  

The material which acquires the electrons will get negatively charged.

While combing the hairs by using a comb the combs become negatively charged. Here, the electrons are transferred from hair to the comb. Therefore, the comb will gain electrons and it will get negatively charged.

Therefore, "the comb gains electrons" is true.

work: w = fd (given)

work done by chet   =50*1 = 50 j

work done by mika =40*2 = 80 j

work done by sara =30*1.5 = 45 j

work done by bill =60*0.5 = 30 j

students in order from the greatest amount of work done to the least is mika> chet> sara> bill

hence option (b) is correct.