Question

The phase difference between the flux linkage and the induced e.m.f. in a rotating coil in a uniform magnetic field is:

• A. $\pi$
• B. $\frac{\pi }{2}$
• C. $\frac{\pi }{4}$
• D. $\frac{\pi }{6}$

Answer 1

The correct option is B $\frac{\pi }{2}$

$\varphi =BAcos\theta$ where $\theta$ is the angle between area and field
$e=\frac{-d\varphi }{dt}=-BAsin\theta .\frac{d\theta }{dt}=BA\left(\frac{d\theta }{dt}\right)cos(90+\theta )$
Here phase difference = ${90}^{\circ }$.