Question

The magnetic field normal to a coil of 40 turns area $3c{m}^2$ is B = (250 - 0.6t) millitesla. The emf induced in the coil will be

• A. $1.8\mu V$
• B. $3.6\mu V$
• C. $5.4\mu V$
• D. $7.2\mu V$

Answer 1

The correct option is D $7.2\mu V$

Given,

Magnetic field, $B=(250-0.6t)\times {10}^{-3}T$

$\frac{dB}{dt}=-0.6\times {10}^{-3}T{s}^{-1}$

Area, $A=3\times {10}^{-4}{m}^2$

$\epsilon =-NA\frac{dB}{dt}=-40\times (3\times {10}^{-4})(-0.6\times {10}^{-3})=7.2\mu V$

Hence, emf is $7.2\mu V$