Question -
Answer -
(a) Whenpolythene is rubbed against wool, a number of electrons get transferred fromwool to polythene. Hence, wool becomes positively charged and polythene becomesnegatively charged.
Amount of charge on the polythenepiece, q = −3 × 10−7 C
Amount of charge on anelectron, e = −1.6 × 10−19 C
Number of electrons transferredfrom wool to polythene = n
n can becalculated using the relation,
q = ne= 1.87 × 1012
Therefore, the number ofelectrons transferred from wool to polythene is 1.87 × 1012.
(b) Yes.
There is a transfer of masstaking place. This is because an electron has mass,
me =9.1 × 10−3 kg
Total mass transferred topolythene from wool,
m = me ×n
= 9.1 × 10−31 ×1.85 × 1012
= 1.706 × 10−18 kg
Hence, a negligible amount ofmass is transferred from wool to polythene.