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

The Correct Option is B

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:

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