Question

A rectangular coil $0.20\, m \times 0.10 m$, of $100$ turns, rotates in a magnetic field of $3 \times 10^{-3} T$ with a frequency of $20 \,Hz$, about an axis normal to the magnetic field. What is the maximum value of induced emf?

• A. $0.12 \pi V$
• B. $0.18 \pi V$
• C. $0.24 \pi V$
• D. $0.30 \pi V$

Answer 1

Answer: (C)

$\varepsilon=B A N \omega \sin \omega t$
$\varepsilon_{\max } =B A N \omega=B A N(2 \pi v) $
$=\left(3 \times 10^{-3} T \right) \cdot(0.2 m \times 0.1 m )(100)(2 \pi \times 20 Hz ) $
$=0.24 \pi V $