A wire, bent into the shape of a right angled triangle PQR,PQR, lies with its side PRPR parallel to a current carrying wire, and side QRQR perpendicular to it. The loop lies in the plane of the wire. EMF induced in the loop when it is moved with constant speed along PRPR is ε1ε1 and it is ε2ε2 when moved along QRQR with the same constant speed. Then,

1. ε1=0,ε20ε1=0,ε20
2. ε10,ε2=0ε10,ε2=0
3. ε1=0,ε2=0ε1=0,ε2=0
4. ε10,ε20ε10,ε20

Subtopic:  Motional emf |
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In the circuit shown in the adjoining figure, the switch was kept at the position 1 for a long time. The switch K is suddenly (and smoothly) shifted to position 2.
The current through the cell, just after the shift, is:
1. V02R 2. V0R
3. 3V04R 4. zero
Subtopic:  LR circuit |
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A straight horizontal wire of mass m and length l, and having a negligible resistance can slide freely on a pair of conducting parallel rails, placed vertically. The rails are connected at the top by a capacitor C. A uniform magnetic field B exists in the region, perpendicular to the plane of the rails. The wire:
           
1. falls with uniform velocity.
2. accelerates down with acceleration less than g.
3. accelerates down with acceleration equal to g.
4. moves down and eventually comes to rest.
Subtopic:  Motional emf |
 71%
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An inductor (L) and a resistor (R) are connected in series and a battery is connected, as shown in the figure. Once the current becomes steady, the power in the resistance is PR and the energy stored in the inductor is UL. The switch is suddenly (and smoothly) toggled to the position B allowing the inductor to discharge. The time in which the energy stored becomes 12 its initial value is:
                           
 
1. ULPR 2. UL ln2PR
3. 2UL ln2PR 4. 2ULPR
Subtopic:  LR circuit |
 54%
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A circular wire of radius R is placed in a uniform magnetic field B, which acts into the plane as shown. The wire is given a half-turn about a diameter. The resistance per unit length of the wire is λ. The total charge flowing through the wire is:
                              

 
1. 2BRλ 2. BRλ
3. BR2λ 4. zero
Subtopic:  Motional emf |
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The self-inductance of a long solenoid of cross-section A, total length L and total number of turns N, is (approximately):
1. μ0ALN 2. μ0ALN2
3. μ0L3AN 4. μ0L3AN2
Subtopic:  Self - Inductance |
 81%
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The DC time constant of an L-R circuit is the same as that of an R-C circuit where the inductor in the first circuit was replaced by a capacitor. The value of the resistance R equals:
1. 12πLC 2. LC
3. 2πLC 4. 2LC
Subtopic:  LR circuit |
 58%
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A 3 μF capacitor is charged with 6 μC and connected across a 1 mH inductance. The rate of change of current is:
1. 2 A/s
2. 2×103 A/s
3. 2×103 A/s
4. 2×106 A/s
Subtopic:  Self - Inductance |
 72%
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A conducting circular wire of radius r is moving with constant velocity v towards the right in a uniform magnetic field B. We consider two points X,Y such that chord XY is perpendicular to the velocity v and is at a distance x from the centre (O) of the circle. The EMF induced between X,Y is ε. Then, ε is proportional to:
                
1. x
2. r2x2
3. r
4. xr2x2
Subtopic:  Motional emf |
 73%
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Given below are two statements: 
Assertion (A): Faraday's law of electromagnetic induction is a consequence of Biot-Savart's law.
Reason (R): Currents cause magnetic fields and interact with magnetic flux.
 
1. (A) is True but (R) is False.
2. (A) is False but (R) is True.
3. Both (A) and (R) are True and (R) is the correct explanation of (A).
4. Both (A) and (R) are True but (R) is not the correct explanation of (A).
Subtopic:  Faraday's Law & Lenz Law |
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