Electro Magnetic Induction And Alternating Currents Question 371
Question: A coil has 2000 turns and area of $ 70cm^{2} $ . The magnetic field perpendicular to the plane of the coil is $ 0.3Wb/m^{2} $ and takes 0.1sec to rotate through $ 180^{o} $ . The value of the induced e.m.f. will be [MP PET 1993; Similar to AIIMS 1997]
Options:
A) $ 8.4V $
B) $ 84V $
C) $ 42V $
D) $ 4.2V $
Show Answer
Answer:
Correct Answer: B
Solution:
$ e=-\frac{NBA(\cos {\theta_{2}}-\cos {\theta_{1}})}{\Delta t} $ $ =-2000\times 0.3\times 70\times {{10}^{-4}}\frac{(\cos 180-\cos 0)}{0.1} $
$ \Rightarrow e=84\ V $
