Electromagnetic Induction Question 4
Question 4 - 29 January - Shift 1
A certain elastic conducting material is stretched into a circular loop. It is placed with its plane perpendicular to a uniform magnetic field $B=0.8 T$. When released the radius of the loop starts shrinking at a constant rate of $2 cm^{-1}$. The induced emf in the loop at an instant when the radius of the loop is $10 cm$ will be $mV$.
Show Answer
Answer: (10)
Solution:
$EMF=\frac{d}{dt}(B \pi r^{2})$
$=2 B \pi r \frac{dr}{dt}=2 \times \pi \times 0.1 \times 0.8 \times 2 \times 10^{-2}$
$=2 \pi \times 1.6=\mathbf{1 0 . 0 6}[$ round off $\mathbf{1 0 . 0 6}=\mathbf{1 0}]$
