Question

What do you think why the third pin in the three pin plug is little longer and thicker than the other two in a three pin plug?​

Answer 1

Its longer than the other two pins because when you insert the plug,the earth pin will first come in contact with the power supply before the other two(live and neutral) so that any unwanted charges which may be in the circuit will be removed(grounded) before the other two pins go inside the terminals.