What does a rheostat control?

What does Rheostat controls? electron drift velocity or quantity of electrons? We know I=nAve I=current n=quantity of electron A=conductor area e=electron charge v=drift velocity (Asked  Partha)

Random collection of Physics Viva Questions

State the Principle of a potentiometer. (The students say that potential drop is proportional to length but the constant quantities are not mentioned) How can we increase the sensitivity of a potentiometer? Define figure of merit of a galvanometer. Which has more resistance – a galvanometer or a milliammeter? How does an LED emit light?…… Continue reading Random collection of Physics Viva Questions

Why direct currents aren’t used in Home circuits?

How can an alternating current change its direction while moving in a wire or any conductor? Why direct currents aren’t used in Home circuits?
RAHUL ASKED
Answer:
Alternating current is produced by rotating a coil in a strong magnetic field (or …