If v, w, q stand for voltage, energy and charge, then v can be expressed

The energy stored in the magnetic field of solenoid $$30$$ $$cm$$ long and $$3$$ $$cm$$ diameter wound with $$1000$$ turns of wire carrying a current of $$10$$ $$A$$ is

Which semiconductor power device out of the following is not a current triggered device?

The Triac can be used only in