Flourescent tubes produces light by the

The energy stored in an inductor of inductance 5mH when a current of 6A flows through it is

A steady current of 2A flows in a coil of emf 12V for 0.4s. A back emf of 3V was induced during this period. The stored energy in the loop that can be utilized is

The instrument used for securing a large number of similar charges by induction is called