Physics-
General
Easy
Question
AB is a resistance less conducting rod which forms a diameter of a conducting ring of radius r rotating in a uniform magnetic field B as shown. The resistors 
and 
do not rotate. Then current through the resistor R1 is
The correct answer is:
he equivalent diagram is : The induced emf across the centre and any point on the circumference is :
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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 
(tesla/second). An electron of charge q, placed at the point P on the periphery of the field experiences an acceleration:
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 (tesla/second). An electron of charge q, placed at the point P on the periphery of the field experiences an acceleration:
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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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A vertical conducting ring of radius R falls vertically with a speed V in a horizontal uniform magnetic field B which is perpendicular to the plane of the ring :
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A and B are two metallic rings placed at opposite sides of an infinitely long straight conducting wire as shown. If current in the wire is slowly decreased, the direction of induced current will be :
A and B are two metallic rings placed at opposite sides of an infinitely long straight conducting wire as shown. If current in the wire is slowly decreased, the direction of induced current will be :
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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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Switch S is closed for a long time at t = 0. It is opened, then:
Switch S is closed for a long time at t = 0. It is opened, then:
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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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In the figure shown the section EDFG is fixed. A rod having resistance 'R' is moved with constant velocity in a uniform magnetic field B as shown in the figure. DE & FG are smooth and resistance less. Initially capacitor is uncharged. The charge on the capacitor:
In the figure shown the section EDFG is fixed. A rod having resistance 'R' is moved with constant velocity in a uniform magnetic field B as shown in the figure. DE & FG are smooth and resistance less. Initially capacitor is uncharged. The charge on the capacitor:
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Figure shows three regions of magnetic field, each of area A, and in each region magnitude of magnetic field decreases at a constant rate 
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is induced electric field then value of line integral 
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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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In the figure shown a square loop PQRS of side 'a' and resistance 'r' is placed near an infinitely long wire carrying a constant current I. The sides PQ and RS are parallel to the wire. The wire and the loop are in the same plane. The loop is rotated by 
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Two metallic rings A and B, identical in shape and size but having different resistivities 
and 
, are kept on top of two identical solenoids as shown in the figure. When current I is switched on in both the solenoids in identical manner, the rings A and B jump to heights hA and hB , respectively, with 
. The possible relation(s) between their resistivities and their masses 
and 
is(are)
Two metallic rings A and B, identical in shape and size but having different resistivities and , are kept on top of two identical solenoids as shown in the figure. When current I is switched on in both the solenoids in identical manner, the rings A and B jump to heights hA and hB , respectively, with . The possible relation(s) between their resistivities and their masses and is(are)
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