In which of the following situations will the potential difference induced in the coil be the maximum?
(i) A bar magnet moving with a speed of 2m/s towards a stationary coil
(ii) A coil moving with a speed of 2m/s towards a stationary bar magnet
(iii) A coil and a bar magnet moving in the same direction with the speed of 2m/s.
(iv) A coil and a bar magnet moving towards each other with the speed of 2m/s.

Correct option is A

The correct answer is option ( a ) iv

Information booster :

• Electromagnetic Induction:

  1. The phenomenon of inducing an electromotive force (emf) in a conductor by changing the magnetic field around it is called electromagnetic induction.
  2. This can be achieved by relative motion between a conductor and a magnetic field.

• Factors affecting induced emf:

  1. Strength of the magnetic field: A stronger magnetic field will induce a larger emf.
  2. Speed of relative motion: Faster relative motion between the conductor and the magnetic field will induce a larger emf.
  3. Orientation of the conductor: The emf is maximum when the conductor moves perpendicular to the magnetic field lines.

Analysis of the given situations:

• (i) & (ii): In these cases, the relative speed between the magnet and the coil is 2 m/s. However, the orientation of the coil and the direction of motion may not be optimal for maximum emf.
• (iii): Since the coil and the magnet are moving in the same direction with the same speed, there is no relative motion between them. Hence, no emf will be induced.
• (iv): In this situation, the relative speed between the magnet and the coil is 4 m/s (2 m/s + 2 m/s). This is the highest relative speed among the given options. Since the coil and the magnet are moving towards each other, the orientation can be optimized to maximize the emf.

Therefore, the potential difference induced in the coil will be maximum when the coil and the bar magnet are moving towards each other with the speed of 2 m/s (option iv).