Question

Fig. shown a square loop if side 5 cm being moved towards right at a constant speed of 1 cm/s. The front edge enters the 20 cm wide magnetic field at t=0. find the emf indeed in the loop at total heat produced during the interval 0 to 30 s if the resistance of the loop is 4.5 m$\Omega$.

t = 2 s

t = 10 s

t = 22 s

t = 30 s.

Answer 1

(a) At t = 2sec,

distance moved = $2\times 1cm/sec$

$E=\frac{d\varphi }{dt}=\frac{0.6\times (2\times 5-0)\times {10}^{-4}}{2}$

= $3\times {10}^{-4}V$

(b) At t = 10sec

distance moved = $10\times 1=10cm/sec$

The flux linked does not change with time

∴ E = 0

(c) At t = 22sec

distance = $22\times 1=22cm/sec$

$E=\frac{d\varphi }{dt}=B\times \frac{dA}{dt}=3\times {10}^{-4}V$

The loop is moving out of the field and 2cm outside.

(d) At t = 30sec

The loop is total outside and flux linked = 0.