## A line charge λ per unit length is lodged uniformly onto the rim of a wheel of mass M and radius R. The wheel has light non-conducting spokes and is free to rotate without friction about its axis (Below Fig.). A uniform magnetic field extends over a circular region within the rim. It is given by,

A line charge λ per unit length is lodged uniformly onto the rim of a wheel of mass M and radius R. The wheel has light non-conducting spokes and is free to rotate without friction about its axis (Below Fig.). A uniform Read More …

## (a) Obtain an expression for the mutual inductance between a long straight wire and a square loop of side a as shown in below fig.

(a) Obtain an expression for the mutual inductance between a long straight wire and a square loop of side a as shown in below fig. (b) Now assume that the straight wire carries a current of 50 A and the loop Read More …

## An air-cored solenoid with length 30 cm, area of cross-section  25 cm2 and number of turns 500, carries a current of 2.5 A. The current is suddenly switched off in a brief time of  10-3 s  . How much is the average back emf induced across the ends of the open switch in the circuit? Ignore the variation in magnetic field near the ends of the solenoid.

An air-cored solenoid with length 30 cm, area of cross-section  25 cm2 and number of turns 500, carries a current of 2.5 A. The current is suddenly switched off in a brief time of  10-3 s  . How much is the average back Read More …

## Figure 6.20 shows a metal rod PQ resting on the smooth rails AB and positioned between the poles of a permanent magnet. The rails, the rod, and the magnetic field are in three mutual perpendicular directions. A galvanometer G connects the rails through a switch K. Length of the rod = 15 cm, B = 0.50 T, resistance of the closed loop containing the rod = 9.0 mΩ. Assume the field to be uniform. a) Suppose K is open and the rod is moved with a speed of 12 cm s−1 in the direction shown. Give the polarity and magnitude of the induced emf.

Figure 6.20 shows a metal rod PQ resting on the smooth rails AB and positioned between the poles of a permanent magnet. The rails, the rod, and the magnetic field are in three mutual perpendicular directions. A galvanometer G connects the rails Read More …

## It is desired to measure the magnitude of field between the poles of a powerful loud speaker magnet. A small flat search coil of area 2 2 cm with 25 closely wound turns, is positioned normal to the field direction, and then quickly snatched out of the field region. Equivalently, one can give it a quick 90 turn to bring its plane parallel to the field direction). The total charge flown in the coil (measured by a ballistic galvanometer connected to coil) is 7.5 mC. The combined resistance of the coil and the galvanometer is 0.50 Ω . Estimate the field strength of magnet.

It is desired to measure the magnitude of field between the poles of a powerful loud speaker magnet. A small flat search coil of area 2 2 cm with 25 closely wound turns, is positioned normal to the field direction, and then Read More …

## A square loop of side 12 cm with its sides parallel to X and Y axes is moved with a velocity of 8 cm s-1  in the positive x-direction in an environment containing a magnetic field in the positive z-direction. The field is neither uniform in space nor constant in time. It has a gradient of     10-3 T cm-1 along the negative x-direction (that is it increases by 10-3 T cm-1 as one moves in the negative x-direction), and it is decreasing in time at the rate of 10-3 T cm-1 Determine the direction and magnitude of the induced current in the loop if its resistance is 4.50 . mΩ

A square loop of side 12 cm with its sides parallel to X and Y axes is moved with a velocity of 8 cm s-1  in the positive x-direction in an environment containing a magnetic field in the positive z-direction. The field Read More …

## Suppose the loop in Exercise 6.4 is stationary but the current feeding the electromagnet that produces the magnetic field is gradually reduced so that the field decreases from its initial value of 0.3 T at the rate of 0.02 T s−1. If the cut is joined and the loop has a resistance of 1.6 Ω how much power is dissipated by the loop as heat? What is the source of this power?

Suppose the loop in Exercise 6.4 is stationary but the current feeding the electromagnet that produces the magnetic field is gradually reduced so that the field decreases from its initial value of 0.3 T at the rate of 0.02 T s−1. If Read More …

## A jet plane is travelling towards west at a speed of 1800 km/h. What is the voltage difference developed between the ends of the wing having a span of 25 m, if the Earth’s magnetic field at the location has a magnitude of  5 ×10-4 T and the dip angle is 30°.

A jet plane is travelling towards west at a speed of 1800 km/h. What is the voltage difference developed between the ends of the wing having a span of 25 m, if the Earth’s magnetic field at the location has a magnitude Read More …

## A pair of adjacent coils has a mutual inductance of 1.5 H. If the current in one coil changes from 0 to 20 A in 0.5 s, what is the change of flux linkage with the other coil?

A pair of adjacent coils has a mutual inductance of 1.5 H. If the current in one coil changes from 0 to 20 A in 0.5 s, what is the change of flux linkage with the other coil?

## Current in a circuit falls from 5.0 A to 0.0 A in 0.1 s. If an average emf of 200 V induced, give an estimate of the self-inductance of the circuit.

Current in a circuit falls from 5.0 A to 0.0 A in 0.1 s. If an average emf of 200 V induced, give an estimate of the self-inductance of the circuit.

## A horizontal straight wire 10 m long extending from east to west is falling with a speed of 1 5.0 m s-1 ,  at right angles to the horizontal component of the earth’s magnetic field, 0.30 ×10-4 Wb m .

A horizontal straight wire 10 m long extending from east to west is falling with a speed of 1 5.0 m s-1 ,  at right angles to the horizontal component of the earth’s magnetic field, 0.30 ×10-4 Wb m . (a) What Read More …

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