Question

The resistance of a coil is 5 ohm and a current of 2.0 A is included in it due to a varying magnetic field, the rate of change og magnetic flux in it will be -

• A. 0.5 Wb/s
• B. 0.05 Wb/s
• C. 1 Wb/s
• D. 10Wb/s

Answer 1

Answer: (D)

10Wb/s

Given: $I=2A$

$R=5\Omega$

To find: $\frac{\Delta \varphi }{\Delta t}=?$

Solution: As we know that,

e.m.f induced in coil, $\epsilon =\frac{\Delta \varphi }{\Delta t}$ $....\left(1\right)$

and also,

e.m.f induced in coil, $\epsilon =I\ast R$ $....\left(2\right)$

using $e{q}^n\left(1\right)$ and $e{q}^n\left(2\right)$, we get

$I\ast R=\frac{\Delta \varphi }{\Delta t}$

so, $\frac{\Delta \varphi }{\Delta t}=2\ast 5$

$\frac{\Delta \varphi }{\Delta t}=10Wb/s$