Question: A lamp in a circuit consisting of a coil of large number of turns and a battery does not light up to full brilliance instantly on switching on the circuit . Why ?
Ans. When circuit is switched on , current increases through the lamp and also through the coil . An induced e.m.f developes in the coil which opposes the growth of current . As current takes time to grow to maximum value , the lamp does not light instantly upto full brilliance .