Question

A copper rod $10$cm long rotates $1800$ times per minute about an axis passing through one end at a right angle to the rod. A uniform magnetic field of $1$ tesla is applied perpendicular to the plane of rotation. The voltage induced between the ends of the rod is

• A. $0.235$V
• B. $0.942$V
• C. $2.35$V
• D. zero

Answer 1

Answer: (B)

$0.942$V

Velocity induced $=\frac{B\omega l^2}{2}$

$L=$ length of rod$=10cm=0.1m$

$\omega =1800rpm=\frac{1800\times 2\pi }{60}{s}^{-1}$

$EM{F}_{induced}=\frac{1\times 1800\times 2\pi \times 0.1\times \mathrm{0.0.1}}{2\times 60\times 100}=0.942V$