Question

A 2 m long metallic rod rotates with an angular frequency of 200 rad s-1 about an axis normal to the rod passing through its one end. The other end of the rod is in contact with a circular metallic ring. A constant magnetic field of 0.5 T parallel to the axis exists everywhere. The emf developed between the centre and the ring is

• A. 100 V
• B. 200 V
• C. 300 V
• D. 400 V

Answer 1

Answer: (B)

200 V

Answer 2

The emf developed between the centre and the ring is

$\varepsilon = \frac{1}{2}Bl^{2}\omega = \frac{0.5 \times 2^{2} \times 200}{2} = 200V$