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A current carrying loop of radius R and mass'm' is placed inside a uniform magnetic field an shown

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Important Questions on Magnetic Effects of Current and Magnetism

MEDIUM
A conducting circular loop of radius r carries a constant current i. It is placed in a uniform magnetic field B0 such that B0 is perpendicular to the plane of the loop. The magnetic force acting on the loop is
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In a thin rectangular metallic strip a constant current I flows along the positive x - direction, as shown in the figure. The length, width and thickness of the strip are l, w and d, respectively. A uniform magnetic field B  is applied on the strip along positive y - direction. Due to this the charge carries experience a net deflection along the z-direction. This results in accumulation of charge carriers on the surface PQRS and appearance of equal opposite charges on the face opposite to PQRS. A potential difference along the z - direction is thus developed. Charge accumulation continues until the magnetic force is balanced by the electric force. The current is assumed to be uniformly distributed on the cross section of the strip and carried by electrons.

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Consider two different metallic strips (1 and 2) of the same material. Their lengths are the same, widths are w1 and w2 and thicknesses are d1 and d2 , respectively. Two points K and M are symmetrically located on the opposite faces parallel to the x - y plane (see figure). V1 and V2 are the potential differences between K and M in strips 1 and 2 respectively. Then, for a given current I flowing through them in a given magnetic field strength B , the correct statement(s) is (are)

MEDIUM
A metallic rod of mass per unit length 0.5 kg m-1 is lying horizontally on a smooth inclined plane which makes an angle of 30° with the horizontal. The rod is not allowed to slide down by flowing a current through it when a magnetic field of induction 0.25 T is acting on it in the vertical direction. The current flowing in the rod to keep it stationary is
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An infinitely long current carrying wire and a small current carrying loop are in the plane of the paper as shown. The radius of the loop is a and distance of its centre from the wire is d da. If the loop applies a force F on the wire then:
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MEDIUM
In an experiment, setup A consists of two parallel wires which carry currents in opposite directions as shown in the figure. A second setup B is identical to setup A, except that there is a metal plate between the wires.

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Let FA and FB be the magnitude of the force between the two wires in setup A and setup B, respectively.

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A square loop of side 2a, and carrying current I is kept in XZ plane with its centre at origin. A long wire carrying the same current I is placed parallel to the z-axis and passing through the point (0, b, 0),(b>> a). The magnitude of the torque on the loop about z-axis is given by.
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A thin semicircular conducting ring PQR of radius r is falling with its plane vertical in a horizontal magnetic field B, as shown in figure. The potential difference developed across the ring when its speed is v, is:
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EASY

The magnitude and direction of a force vector acting on a unit length of thin wire carrying a current I at point O, if the wire has a semicircular shape of radius R as shown in the figure.

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HARD
A conductor lies along the z-axis at - 1.5 z <1.5 m  and carries a fixed current of 10.0 A in - a ^ z  direction (see figure). For a field B = 3.0 × 1 0 - 4  e - 0.2x  a ^ y  T, find the power required to move the conductor at constant speed to x = 2.0 m, y = 0 m in 5 × 1 0 - 3  s . Assume parallel motion along the x-axis.

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HARD
A Conductor (shown in the figure) carrying constant current I is kept in the x - y plane in a uniform magnetic field B . If F is the magnitude of the total magnetic force acting on the conductor, then the correct statement(s) is (are)


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HARD

A circular coil of radius R and N turns has negligible resistance. As shown in the schematic figure, its two ends are connected to two wires and it is hanging by those wires with its plane being vertical. The wires are connected to a capacitor with charge Q through a switch. The coil is in a horizontal uniform magnetic field Bo parallel to the plane of the coil. When the switch is closed, the capacitor gets discharged through the coil in a very short time. By the time the capacitor is discharged fully, magnitude of the angular momentum gained by the coil will be (assume that the discharge time is so short that the coil has hardly rotated during this time)

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EASY
A square loop ABCD carrying a current i , is placed near and coplanar with a long straight conductor XY carrying a current I , the net force on the loop will be:

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MEDIUM

A copper rod of mass m slides under gravity on two smooth parallel rails l distance apart and set an angle θ to the horizontal. At the bottom, the rails are joined by a resistance R in figure. There is a uniform magnetic field B perpendicular to the plane of the rails. The terminal velocity of rod is

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HARD

An elliptical loop having resistance R, of semi major axis a , and semi minor axis b  is placed in a magnetic field as shown in the figure. If the loop is rotated about the x-axis with angular frequency ω, the average power loss in the loop due to Joule heating is :

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EASY
A conducting circular loop of radius r carries a constant current i. It is placed in an uniform magnetic field B0 such that B0 is perpendicular to the plane of the loop. The magnetic force acting on the loop is.
EASY
A wire of length L carries current I along x axis. A magnetic field B=B0(ı^-ȷ^-k^)T acts on the wire. The magnitude of magnetic force acting on the wire is
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As shown in the figure, a wire is bent to form a D -shaped closed loop, carrying current I, where the curved part is a semi-circle of radius R. The loop is placed in a uniform magnetic field B, which is directed into the plane of the paper. The magnetic force felt by the closed loop is
HARD

In a thin rectangular metallic strip a constant current I flows along the positive x - direction, as shown in the figure. The length, width and thickness of the strip are l, w and d, respectively. A uniform magnetic field B  is applied on the strip along positive y - direction. Due to this the charge carries experience a net deflection along the z-direction. This results in accumulation of charge carriers on the surface PQRS and appearance of equal opposite charges on the face opposite to PQRS. A potential difference along the z - direction is thus developed. Charge accumulation continues until the magnetic force is balanced by the electric force. The current is assumed to be uniformly distributed on the cross section of the strip and carried by electrons.

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Consider two different metallic strips (1 and 2) of same dimensions (length l , width w and thickness d ) with carrier densities n1 and n2 , respectively. Strip 1 is placed in magnetic field B1 and strip 2 is placed in magnetic field B2 , both along positive y -directions. Then V1 and V2 are the potential differences developed between K and M in strips 1 and 2 respectively. Assuming that the current I is the same for both strips, the correct option(s) is (are)

HARD

A wire carrying current I is tied between points P and Q and is in the shape of a circular arc of radius R due to a uniform magnetic field B (perpendicular to the plane of the paper, as shown in the figure) in the vicinity of the wire. If the wire subtends an angle 2θo at the center of the circle (of which it forms an arch) then the tension in the wire is:
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MEDIUM
Two coaxial solenoids of different radii carry current I in the same direction. Let F1  be the magnetic force on the inner solenoid due to the outer one and F2 be the magnetic force on the outer solenoid due to the inner one. Then: