Electromagnetic Induction Physics - Electromagnetic Induction

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.

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.

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.

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

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.

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.

A pivoted aluminium bar falls much more slowly through a small region containing a magnetic field than a similar bar of an insulating material. Explain.

A wire-loop confined in a plane is rotated in its own plane with some angular velocity. A uniform magnetic field exists in the region. Find the emf induced in the loop.

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.

Two circular loops are placed coaxially but separated by a distance. A battery is suddenly connected to one of the loops establishing a current in it. Will there be a current induced in the other loop? If yes, when does the current start and when does it end? Do the loops attract each other or do they repel?

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.

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.

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

A 20cm long conducting rod is set into pure translation with a uniform velocity of 10cm/s^-1 perpendicular to its length. A uniform magnetic field of magnitude 0.10T exists in a direction perpendicular to the plane of motion.

1. Find the average magnetic force on the free electrons of the rod.
2. For what electric field inside the rod, the electric force on a free elctron will balance the magnetic force? How is this electric field created?
3. Find the motional emf between the ends of the rod.

1. The magnetic field in a region varies as shown in figure. Calculate the average induced emf in a conducting loop of area 2.0 × 10^-3m² placed perpendicular to the field in each of the 10ms intervals shown.
2. In which intervals is the emf not constant? Neglect the behaviour near the ends of 10ms intervals.

Find the mutual inductance between the straight wire and the square loop of figure.