Question

A thin circular ring of area A is perpendicular to uniform magnetic field of induction B. A small cut is made in the ring and a galvanometer is connected across the ends such that the total resistance of circuit is R. When.the ring is suddenly squeezed to zero area, the charge flowing through the galvanometer is

• A. $\frac{BR}{A}$
• B. $\frac{AB}{R}$
• C. ABR
• D. ${B^2\,A}{R^2}$

Answer 1

Answer: (B)

$\frac{AB}{R}$

Answer 2

$Q = \frac{\Delta \phi}{R} - \frac{\phi_2 - \phi_1}{R} = \frac{BA - 0}{R} = \frac{BA}{R}$ = $6 \times 10^{-3}$ = 6mWb