Physics-
General
Easy
Question
A conducting ring of radius r with a conducting spoke 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 
is –
The correct answer is:
Considering pure rolling of OA about A: the induced emf across OA will be :
From Lenz law, O will be the negative end, while A will be the positive end.
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AB and CD are fixed conducting smooth rails placed in a vertical plane and joined by a constant current source at its upper end. PQ is a conducting rod which is free to slide on the rails. A horizontal uniform magnetic field exists in space as shown. If the rod PQ is released from rest then
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A uniform magnetic field of induction B is confined to a cylindrical region of radius R. The magnetic field is increasing at a constant rate of 
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In the circuit shown in figure, the switch S was initially at position 1. After sufficiently long time, the switch S was thrown from position 1 to position 2. The voltage drop across the resistor at that instant is :
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Two identical conducting rings A & B of radius R are in pure rolling over a horizontal conducting plane with same speed (of center of mass)u but in opposite direction. A constant magnetic field B is present pointing inside the plane of paper. Then the potential difference between the highest points of the two rings, is:
Two identical conducting rings A & B of radius R are in pure rolling over a horizontal conducting plane with same speed (of center of mass)u but in opposite direction. A constant magnetic field B is present pointing inside the plane of paper. Then the potential difference between the highest points of the two rings, is:
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Figure shows a square loop of side 1 m and resistance 1 
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A constant force F is being applied on a rod of length 'l' kept at rest on two parallel conducting rails connected at ends by resistance R in uniform magnetic field B as shown
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In the figure shown, the magnet is pushed towards the fixed ring along the axis of the ring and it passes through the ring
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PQ is an infinite current carrying conductor. AB and CD are smooth conducting rods on which a conductor EF moves with constant velocity V as shown. The force needed to maintain constant speed of EF is.
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A wooden stick of length 
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physics-General
