Question

A magnet is taken towards a conducting ring in such a way that a constant current of 10$mA$ is induced in it. The total resistance of the ring is $0.5\Omega$. In $5s$, the magnetic flux through the ring changes by

• A. $0.25m$ $Wb$
• B. $25m$ $Wb$
• C. $50m$ $Wb$
• D. $15m$ $Wb$

Answer 1

The correct option is B $25m$ $Wb$

$\Delta q=\frac{\Delta \varphi }{R}$

or $i\Delta t=\frac{\Delta \varphi }{R}$

$\therefore$ $\Delta \varphi =i\left(\Delta t\right)R$

$=(10\times {10}^{-3})\left(5\right)\left(0.5\right)$

$=25m$ $Wb$