Question 1:
What is the meaning of electromagnetic induction?
Answer:
Electromagnetic induction is the production of an induced e.m.f. in a conductor when there is relative motion between the conductor and a magnetic field or when the conductor is in a changing magnetic field.
What is the meaning of electromagnetic induction?
Answer:
Electromagnetic induction is the production of an induced e.m.f. in a conductor when there is relative motion between the conductor and a magnetic field or when the conductor is in a changing magnetic field.
Question 2:
(a) State Faraday’s law.
(b) Use Faraday’s law to explain the effect of the speed of rotation of the coil on the magnitude of the induced e.m.f. in a current generator.
Answer:
(a) Faraday’s law states that the magnitude of induced e.m.f. is directly proportional to the rate of cutting of magnetic flux.
(b) When a coil rotates and cuts magnetic field lines, an e.m.f. is induced in the coil. If the speed of rotation is increased, the rate of cutting of magnetic flux increases. According to Faraday’s law, the induced e.m.f. increases.
(a) State Faraday’s law.
(b) Use Faraday’s law to explain the effect of the speed of rotation of the coil on the magnitude of the induced e.m.f. in a current generator.
Answer:
(a) Faraday’s law states that the magnitude of induced e.m.f. is directly proportional to the rate of cutting of magnetic flux.
(b) When a coil rotates and cuts magnetic field lines, an e.m.f. is induced in the coil. If the speed of rotation is increased, the rate of cutting of magnetic flux increases. According to Faraday’s law, the induced e.m.f. increases.
Question 3:
Figure 4.30 shows a simple pendulum with a bar magnet as the bob oscillating near a copper ring.
(a) Explain the production of current in the copper ring when the bar magnet is moving towards the ring.
(b) At the position of the observer in front of the ring as shown in Figure 4.30, state whether the current in the copper ring is clockwise or anti-clockwise.
(c) Explain the effect of the current in the copper ring on the motion of the bar magnet.
Answer:
(a) When the bar magnet moves towards the copper ring, magnetic field lines are cut by the ring. An induced e.m.f. is produced in the ring. This induced e.m.f. produces an induced current in the copper ring.
(b) Anti-clockwise.
(c) According to Lenz’s law, the anti-clockwise current produces a magnetic north pole to oppose the motion of the bar magnet.
This causes the motion of the bar magnet to be slowed down.
Figure 4.30 shows a simple pendulum with a bar magnet as the bob oscillating near a copper ring.
(a) Explain the production of current in the copper ring when the bar magnet is moving towards the ring.
(b) At the position of the observer in front of the ring as shown in Figure 4.30, state whether the current in the copper ring is clockwise or anti-clockwise.
(c) Explain the effect of the current in the copper ring on the motion of the bar magnet.
Answer:
(a) When the bar magnet moves towards the copper ring, magnetic field lines are cut by the ring. An induced e.m.f. is produced in the ring. This induced e.m.f. produces an induced current in the copper ring.
(b) Anti-clockwise.
(c) According to Lenz’s law, the anti-clockwise current produces a magnetic north pole to oppose the motion of the bar magnet.
This causes the motion of the bar magnet to be slowed down.