Physics-
General
Easy
Question
A conducting rod PQ of length L = 1.0 m is moving with a uniform speed v = 2 m/s in a uniform magnetic field directed into the paper. A capacitor of capacity C = 10 mF is connected as shown in figure. Then
- qA = + 80 mC and qB = – 80 mC
- qA = – 80 mC and qB = + 80 mC
- qA = 0 = qB
- Charge stored in the capacitor increases exponentially with time
The correct answer is: qA = + 80 mC and qB = – 80 mC
Q = CV = C (Bvl) = 10 ´ 10– 6 ´ 4 ´ 2 ´ 1 = 80 mC
According to Fleming's right hand rule induced current flows from Q to P. Hence P is at higher potential and Q is at lower potential. Therefore A is positively charged and B is negatively charged.
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