A polythene piece rubbed with wool is found to have a negative charge of 3 x 10 power-7 C. (a) Estimate the number of electrons transferred (from which to which) (b) Is there a transfer of mass from wool to polythene? | question and answer !

Question:-

A polythene piece rubbed with wool is found to have a negative charge of 3 x 10 power-7 C.

(a) Estimate the number of electrons transferred (from which to which)
(b) Is there a transfer of mass from wool to polythene?

Answer:-

(a) When polythene is rubbed against wool, a number of electrons get transferred from wool to polythene. Hence, wool becomes positively charged and polythene becomes negatively charged.

Amount of charge on the polythene piece 

Amount of charge on an electron, 

Number of electrons transferred from wool to polythene = n



n can be calculated using the relation,



Therefore, the number of electrons transferred from wool to polythene is 

(b) Yes.

There is a transfer of mass taking place. This is because an electron has mass,



Total mass transferred to polythene from wool,



Hence, a negligible amount of mass is transferred from wool to polythene.