Question

ASSERTION- It is more difficult to push a magnet into a coil with more loops.
REASON- Emf induced in the current loop resists the motion of the magnet.
(A) both assertion and reason are correct and reason is the correct explanation for assertion
(B) both assertion and reason are correct but reason is not the correct explanation for assertion
(C) assertion is correct but reason is incorrect
(D) both assertion and reason are incorrect

Answer 1

In this problem, we have to use Faraday’s law of electromagnetic induction. According to Faraday's law, magnetic field induces potential difference inside a conductor placed in it. Faraday’s law says, an emf will be induced in a conductor which is exposed to a changing magnetic field.

Complete step by step answer: Now since the magnet is moving inside the coil the magnetic flux increases and in accordance with Faraday’s law emf is induced. Since, the magnetic flux keeps on increasing, in accordance with Lenz law, emf induced will oppose the motion of the coil. Thus, it becomes more and more difficult to push a magnet into a coil with more loops.
So, both the assertion and reason are correct and reason is the correct explanation for the assertion.

So, the correct statement is (A)

Note: When the magnetic flux associated with a conductor changes then in accordance with Faraday’s law of electromagnetic induction, emf is induced into the coil. Now, according to the Lenz law, the emf induced is such that it opposes the cause which produces it.