Q.
A square loop of wire of side 5 cm is lying on a horizontal table. An electromagnet above and to one side of the loop is turned on, causing a uniform magnetic field down-wards at an angle of 60${^\circ}$ to the vertical as shown in figure. The magnetic induction is 0.50 T. The average induced emf in the loop, if the field increases from zero to its final value in 0.2 s is
A) $5.4\ \times 10^{- 3}\ V$
B) $3.12\ \times 10^{- 3}\ V$
C) 0
D) $25.\ 0 \times 10^{- 3}\ V$
Explanation
(b) $e = \frac{d\phi}{dt} = \ \frac{(NBA\ cos\theta - 0)}{t}$
$= \ \frac{1 \times 0.5 \times 25 \times 10^{- 4}\cos{60{^\circ} - 0}}{0.2}$
$e\ = 3.12\ \times 10^{- 3}$ V.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.