Q. A rectangular coil of 300 turns has an average area of 25 cm$\ \times$10cm. The coil rotates with a speed of 50 cps in uniform magnetic field of strength $4 \times 10^{- 2}T$ about an axis perpendicular to the field. The peak value of the induced emf is (in volt)
A) 300$\pi$
B) 3000$\ \pi$
C) 3 $\pi$
D) 30$\ \pi$
Explanation
(d) Peak value of induced emf in a rectangular coil is
$e = n\ BA\ \omega\sin\theta$
$\ \ \ = 300 \times 4 \times 10^{- 2} \times \left( 25 \times 10 \times 10^{- 4} \right) \times (2\pi \times 50) \times \sin{90{^\circ}}$
$\ \ \ = 30\pi V$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.