Question

A cycle wheel of radius $0.5\, m$ is rotated with constant angular velocity of $10 \,rad/s$ in a region of magnetic field of $0.1\, T$ which is perpendicular to the plane of the wheel. The $EMF$ generated between its centre and the rim is,

• A. 0.25 V
• B. 0.125 V
• C. 0.5 V
• D. zero

Answer 1

Answer: (B)

0.125 V

Answer 2

The formula to calculate emf is

$E = \frac{B \omega l^2}{2}$

$E$ is the electromotive force (EMF) generated.

$B$ is the magnetic field strength (0.1 Tesla in this case).

$l$ is the length, 0.5m

ω is the angular velocity (10 radians per second).

To calculate the value of EMF, let's put the values in the formula:

$E = \frac{B \omega l^2}{2}$
$=\frac{0.1(10)(0.5)^2}{2} = 0.125\,v$