Electro Magnetic Induction And Alternating Currents Question 510
Question: A conducting ring of radius r with a conducting spoke OA is in pure rolling on a horizontal surface in a region having a uniform magnetic field B as shown, v being the velocity of the centre of the ring. Then the potential difference $ V_{0}-V_{A} $ is:
Options:
A) $ \frac{Bvr}{2} $
B) $ \frac{3Bvr}{2} $
C) $ \frac{Bvr}{2} $
D) $ \frac{-3Bvr}{2} $
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Answer:
Correct Answer: C
Solution:
- Considering pure rolling of OA about A: the induced emf across OA will be:
$ | . {\vec{e}} | .=\frac{B\omega {{(r)}^{2}}}{2} $
From lenz law, 0 will be the negative end, while A will be the positive end. Hence $ V_{0}-V_{A}=-\frac{B\omega r^{2}}{2} $
