Question

Assertion (A): It is difficult to move a magnet into a coil of large number of turns when the circuit of the coil is closed.

Reason (R): The direction of induced current in a coil with its circuit closed, due to motion of a magnet, is such that it opposes the cause.

• A. Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A)
• B. Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).
• C. Assertion (A) is true, but Reason (R) is false.
• D. Assertion (A) is false and Reason (R) is also false.

Hint:

Lenz's Law states that the direction of the induced current opposes the change in the magnetic flux, which is the reason why it's difficult to move a magnet into a coil.

Answer 1

The Correct Option is A

The problem involves understanding electromagnetic induction, particularly the concept of Lenz's Law, which explains the direction of induced current. 

• Assertion (A): It is difficult to move a magnet into a coil of large number of turns when the circuit of the coil is closed.
• Reason (R): The direction of induced current in a coil with its circuit closed, due to motion of a magnet, is such that it opposes the cause.

Let's analyze the statements:

• According to Lenz's Law, the induced current in a coil creates a magnetic field that opposes the change in magnetic flux through the coil. Therefore, when a magnet is moved into a coil of wire, the induced current generates a magnetic field opposing the magnet's motion, making it difficult to move the magnet further.
• Consequently, both the assertion and the reason are true.
• The reason correctly explains the assertion because the induced current's opposition to the change (motion of magnet) is the cause of the difficulty in moving the magnet into the coil.

Thus, the correct conclusion is that both Assertion (A) and Reason (R) are true, and Reason (R) is the correct explanation of Assertion (A).