Em Waves Question 90
Question: A circular ring of radius r is placed in a homogeneous magnetic field perpendicular to the plane of the ring. The field B changes with time according to equation $ B=kt, $ where, k is a constant and t is the time). The electric field in the ring is:
Options:
A) $ \frac{kr}{4} $
B) $ \frac{kr}{3} $
C) $ \frac{kr}{2} $
D) $ \frac{k}{2r} $
Show Answer
Answer:
Correct Answer: C
Solution:
[c] $ \oint{\vec{E}.d\vec{\ell }=-\frac{d{\phi _{B}}}{dt}} $ or $ E(2\pi r)=\frac{d}{dt}(kt\times \pi r^{2}) $
$ \
Therefore ,E=\frac{kr}{2} $
BETA
