Fri May 20, 2011 By: Rohan Mehra

In an insulator electrons cannot move outside the body of the insulator.But when we rub glass rod with silk how do electrons get transfered from glass rod to silk as glass rod is an insulator.

Expert Reply
Sat May 21, 2011
This happens due to static charges produced by friction!
When an object is charged by rubbing it against another object,transfer of charges take place i.e. electrons get transfered from glass rod to silk. The two objects get oppositely charged. By convention, it is considered that the charged acquired by the glass rod is positive and charged acquired by the cloth is negative. Therefore, the rod becomes positively charged and the cloth becomes negatively charged.
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