Question

A physicist works in a laboratory where the magnetic field is $2$ $T$. She wears a silver necklace enclosing an area $100$ $c{m}^2$ of field and having a resistance of $0.1$ $\Omega$ . Because of power failure, the field decays to $1$ $T$ in millisecond. The electric charge circulated in the necklace assuming that the magnetic field is perpendicular to area covered by the necklace is

• A. $0.01C$
• B. $0.001C$
• C. $0.1C$
• D. $1.0C$

Answer 1

The correct option is C $0.1C$

$q=\frac{N(B_1-B_2)A}{R}=\frac{1(2-1){10}^{-2}}{0.1}=0.1C$