EASY
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Lenz's law is a consequence of the law of conservation of

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Important Questions on Electromagnetic Induction and Alternating Currents

MEDIUM

A bar magnet is passing through a conducting loop of radius R with velocity v. The radius of the bar magnet is such that it just passes through the loop. The induced e.m.f. in the loop can be represented by the approximate curve:

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EASY

A copper ring having a cut such that it does not form a complete loop is held horizontally and a bar magnet is dropped through the ring with its length along the axis of the ring. Then acceleration of the falling magnet is

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HARD
A metallic ring of radius a and resistance R is held fixed with its axis along a spatially uniform magnetic field whose magnitude is B0sinωt. Neglect gravity. Then,
MEDIUM

The diagram below shows two circular loops of wire A and B centered on and perpendicular to the x-axis, and oriented with their planes parallel to each other. The y-axis passes vertically through loop A (dashed line). There is a current IB in loop B as shown. Possible actions which we might perform on loop A are

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(i) Move A to the right along x-axis closer to B.
(ii) Move A to the left along x-axis away from B.
(iii) As viewed from above, rotate A clockwise about y-axis.
(iv) As viewed from above, rotate A anticlockwise about y-axis Which of these actions will induce a current in A only in the direction shown.

MEDIUM
A coil is placed in a magnetic field B as shown below :
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A current is induced in the coil because B is :
HARD

A square conducting loop is placed near an infinitely long current-carrying wire with one edge parallel to the wire as shown in the figure. If the current in the straight wire is suddenly halved, which of the following statements will be true?
"The loop will "
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EASY
A metal ring is held horizontally and bar magnet is dropped through the ring with its length along the axis of the ring. The acceleration of the falling magnet
EASY
Two identical metallic square loops L1 and L2 are placed next to each other with their sides parallel on a smooth horizontal table. Loop L1 is fixed and a current which increases as a function of time is passed through it. Then loop L2
HARD
A bar magnet falls with its north pole pointing down through the axis of a copper ring. When viewed from above, the current in the ring will be
EASY
A small circular ring is kept inside a larger loop connected to a switch and a battery as shown. The direction of induced current when the switch is made (i) ON (ii) OFF after it was ON for a long time is,


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EASY
Lenz's law of electromagnetic induction corresponds to the
EASY
Assertion: In a given situation, the direction of induced current given by Lenz's law and Fleming's right hand rule is the same.

Reason: Statement of both the laws is the same.
EASY
The north pole of a magnet is falling on a metallic ring as shown in the figure. The direction of induced current, if looked from upside in the ring will be

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MEDIUM
Two circular coils A and B are facing each other as shown in the diagram. The current i through A can be altered. Select the correct option.


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HARD
An electron moves along the line AB with constant velocity V which lies in the same plane as a circular loop of conducting wire as shown in figure. What will be the direction of current induced if any in the loop -


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EASY
An irregular closed loop carrying a current has a shape such that the entire loop cannot lie in a single plane. If this is placed in a uniform magnetic field, the force acting on the loop
MEDIUM
A uniform but time varying magnetic field B (t) exists in a circular region of radius a and is directed into the plane of the paper as shown in figure. The magnitude of induced electric field at point P at a distance r from the centre of the circular region.
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MEDIUM
The variation of induced emf (e) with time (t) in a coil, if a short bar magnet is moved along its axis with a constant velocity, is best represented as

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