Suppose the loop in Textual Exercise 4 is stationary but the current feeding the electromagnet that produces the magnetic field is gradually reduced so that the field decreases from its initial value of 0.3 T at the rate of `0.02Ts^(-1)` .If the cut is joined and the loop has a resistance of `1.6Omega` how much power is dissipated by the loop as heat ? What is the source of this power ?

Explanation

Induced emf =`8 xx 2 xx 10^(-4) xx 0.02 = 3.2 xx 10^(-5) V`
Induced current `= 2 xx 10^(-5) A`
Power loss = `6.4 xx 10^(-10) W`
Source of this power is the external agent responsible for changing the magnetic field with time.