Electromagnetic Induction Physics - Electromagnetic Induction

Consider the situation shown in figure. If the switch is closed and after some time it is opened again, the closed loop will show:

1. An anticlockwise current-pulse.
2. A clockwise current-pulse.
3. An anticlockwise current-pulse and then a clockwise current-pulse.
4. A clockwise current-pulse and then an anticlockwise current-pulse.

Consider the following statements:

1. An emf can be induced by moving a conductor in a magnetic field.
2. An emf can be induced by changing the magnetic field.

1. Both A and B are true.
2. A is true but B is false.
3. B is true but A is false.
4. Both A and B are false.

A conducting loop is placed in a uniform magnetic field with its plane perpendicular to the field. An emf is induced in the loop if:

1. It is translated.
2. It is rotated about its axis.
3. It is rotated about a diameter.
4. It is deformed.

If the magnetic field outside a copper box is suddenly changed, what happens to the magnetic field inside the box? Such low-resistivity metals are used to form enclosures which shield objects inside them against varying magnetic fields.

Consider the energy density in a solenoid at its centre and that near its ends. Which of the two is greater?

A metallic bob A oscillates through the space between the poles of an electromagnet. The oscillations are more quickly damped when the circuit is on, as compared to the case when the circuit is off. Explain.

Consider the self-inductance per unit length of a solenoid at its centre and that near its ends. Which of the two is greater?

An inductor-coil carries a steady-state current of 2.0A when connected across an ideal battery of emf 4.0V. If its inductance is 1.0H, find the time constant of the circuit.

Find the mutual inductance between the circular coil and the loop shown in figure.

A circular coil of one turn of radius 5.0cm is rotated about a diameter w!th a constant angular speed of 80 revolutions per minute. A uniform magnetic field B = 0.010T exists in a direction perpendicular to the axis of rotation. Find

1. The maximum emf induced.
2. The average emf induced in the coil over a long period.
3. The average of the squares of emf induced over a lone period.

Figure shows a metallic square frame of edge a in a vertical plane. A uniform magnetic field B exists in the space in a direction perpendicular to the plane of the figure. Two boys pull the opposite corners of the square to deform it into a rhombus. They start pulling the corners at t = 0 and displace the corners at a uniform speed u.

1. Find the induced emf in the frame at the instant when the angles at these corners reduce to 60°.
2. Find the induced current in the frame at this instant if the total resistance of the frame is R.
3. Find the total charge which flows through a side of the frame by the time the square is deformed into a straight line.

An average emf of 20V is induced in an inductor when the current in it is changed from 2.5A in one direction to the same value in the opposite direction in 0.1s. Find the self-inductance of the inductor.

A short magnet is moved along the axis of a conducting loop. Show that the loop repels the magnet if the magnet is approaching the loop and attracts the magnet if it is going away from the loop.

A metallic loop is placed in a nonuniform magnetic field. Will an emf be induced in the loop?

A long wire carries a current of 4.00A. Find the energy stored in the magnetic field inside a volume ot 1.00mm at a distance of 10.0cm from the wire.

A conducting square loop having edges of length 2.0cm is rotated through 180° about a diagonal in 0.20s. A magnetic field B exists in the region which is perpendicular to the loop in its initial position. If the average induced emf during the rotation is 20mV, find the magnitude of the magnetic field.