Question

A rectangular coil is rotated in a uniform magnetic field about an axis passing through its centre and perpendicular to the direction of the field, then the induced voltage in the coil is directly proportional to the:

• A. Number of turns in the coil
• B. Area of the coil
• C. Angular speed of the coil
• D. All of these

Answer 1

The correct option is D All of these

According to Faraday's law when the magnetic flux linking a circuit changes, an electromotive force is induced in the circuit proportional to the rate of change of the flux linkage.

So, when rectangular coil is rotated in a uniform magnetic field about an axis passing through its centre and perpendicular to the direction of the field, then the induced voltage in the coil $=\frac{d\varphi }{dt}$

$\Rightarrow e.m.f=$$\frac{d\left(NAB\sin \theta \right)}{dt}$

$\Rightarrow e.m.f=$ $NAB\omega \cos \theta$

From here, we can see that induced voltage is proportional to Number of turns in the coil,Area of the coil and Angular speed of the coil also.

Therefore, D is correct option.