| Assertion: Lenz's law is an important consequence of the principle of conservation of energy. |
| Reason: Induced e.m.f. opposes always the change in magnetic flux responsible for its production. |
A) If both assertion and reason are true and reason is the correct explanation of assertion.
B) If both assertion and reason are true and reason is not the correct explanation of assertion.
C) if assertion is true but reason is false.
D) If both assertion and reason are false.
E) If assertion is false but reason is true.
Correct Answer: B
Solution :
Lenz's law states that the direction of induced e.m.f. is always such as to oppose the change that cause it and is a direct consequence of the law of conservation of energy. To prove this let us imagine that when the north pole of the magnet approaches the coil, induced current flows in such a direction as to make the face of the coil facing magnet a south pole. The magnet would be automatically pulled towards the coil (due to attraction between unlike poles), without expenditure of any mechanical energy, it menas electric energy is created out of nothing (or without doing any work) which is against the law of Conservation of energy. Therefore, it is imperative for the induced current to flow in such a direction that the magnetic effect produced by it tends to oppose the very cause, the relative motion between the coil and magnet which produce it.
You need to login to perform this action.
You will be redirected in
3 sec
