Electromagnetic Induction Physics - Electromagnetic Induction

Figure shows a conducting square loop placed parallel to the pole faces of a ring magnet. The Pole-faces have an area of 1cm² each and the field between the poles is 0.10T. The wires making the loop are all outside the magnetic field. If the magnet is removed in 1.0s, what is the average emf induced in the loop?

Figure shows a circular wheel of radius 10.0cm whose upper half, shown dark in the figure, is made of iron and the lower half of wood. The two junctions are joined by an iron rod. A uniform magnetic field B of magnitude 2.00 × 10^-4 T exists in the space above the central line as suggested by the figure. The wheel is set into pure rolling on the horizontal surface. If it takes 2.00 seconds for the iron part to come down and the wooden part to go up, find the average emf induced during this period.

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

An inductor is connected to a battery through a switch. Explain why the emf induced in the inductor is much larger when the switch is opened as compared to the emf induced when the switch is closed.

The two rails of a railway track, insulated from each other and from the ground, are connected to a millivoltmeter. What will be the reading of the millivoltmeter when a train travels on the track at a speed of 180km/h^-1? The vertical component of earth's magnetic field is 0.2 × 10^-4 T and the rails are separated by 1m.

The current generator I_g shown in figure, sends a constant current i through the circuit. The wire cd is fixed and ab is made to slide on the smooth, thick rails with a constant velocity v towards right. Each of these wires has resistance r. Find the current through the wire cd.

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?

Two circular loops are placed with their centres separated by a fixed distance. How would you orient the loops to have:

1. The largest mutual inductance.
2. The smallest mutual inductance?

A metallic metre stick moves with a velocity of 2m/s^-1 in a direction perpendicular to its length and perpendicular to a uniform magnetic field of magnitude 0.2 T. Find the emf induced between the ends of the stick.

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

A rod AB moves with a uniform velocity v in a uniform magnetic field as shown in figure.

1. The rod becomes electrically charged.
2. The end A becomes positively charged.
3. The end B becomes positively charged.
4. The rod becomes hot because of Joule heating.

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.

The current in a discharging LR circuit without the battery drops from 2.0A to 1.0A in 0.10s.

1. Find the time constant of the circuit.
2. If the inductance of the circuit is 4.0H, what is its resistance?

What are the values of the self-induced emf in the circuit of the previous problem at the times indicated therein?

A bicycle is resting on its stand in the east-west direction and the rear wheel is rotated at an angular speed of 100 revolutions per minute. If the length of each spoke is 30.0cm and the horizontal component of the earth's magnetic field is 2.0 × 10^-5 T, find the emf induced between the axis and the outer end of a spoke. Neglect centripetal force acting on the free electrons of the spoke.