Question

Pick out the expression for power in a rectangular conductor from the following.

(a) P=\(\frac {B^2 l^2 v}{R}\)

(b) P=\(\frac {B^2 lv^2}{R}\)

(c) P=\(\frac {B^2 l^2 v^2}{R}\)

(d) P=\(\frac {B^2 l^2 v^2}{R^2}\)

I had been asked this question by my school principal while I was bunking the class.

This intriguing question originated from Energy Consideration: A Quantitative Study topic in section Electromagnetic Induction of Physics – Class 12

Answer 1

The correct choice is (c) P=\(\frac {B^2 l^2 v^2}{R}\)

Easy explanation: In a rectangular conductor, the emf (E) is given ➔ Blv

So, current (I) = \(\frac {E}{R} = \frac {Blv}{R}\)

Power (P) = I^2R

P=\(\frac {B^2 l^2 v^2}{R}\)

The work done is mechanical and this mechanical energy is dissipated as Joule heat.