Rankers Physics

Lenz Law: Practice Problem & Solution

A square coil ACDE with its plane vertical is released from rest in a horizontal uniform magnetic field B of length 2L. The acceleration of the coil is : Lenz Law diagram: A square coil ACDE with its plane vertical
less than g for all the time till the loop crosses the magnetic field completely
less than g when it enters the field and greater than g when it comes out of the field
g all the time
less than g when it enters and comes out of the field but equal to g when it is within the field

Short Solution (Best for NEET):

To solve this problem, we apply the core principles of Lenz Law. Understanding the underlying formula is key to arriving at the correct answer below:

The acceleration is less than 'g' when entering or leaving the field because the changing magnetic flux induces a current that creates an opposing upward force (Lenz's Law).

Once the coil is fully inside the uniform 2L field, the flux is constant, the induced current drops to zero, and the coil falls freely with acceleration equal to g.

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