99 Percentile Qs Bank for JEE MainPhysicsElectromagnetic Induction
A square coil ACDE with its plane vertical is released from rest in a horizontal uniform magnetic field B → which extends over a length 2 L as shown in the figure. The acceleration of the coil is
Options
- Aless than g for all the time till the loop crosses the magnetic field completely
- Bless than g when it enters the field and greater than g when it comes out of the field
- Cequal to g all the time
- Dless than g when it enters and comes out of the field but equal to g when it is within the field
Correct answer
D. less than g when it enters and comes out of the field but equal to g when it is within the field
Step-by-step solution
There will be three situations, (i) When the coil is entering into the field, flux increases and from Lenz's law the induced emf or current opposes the change. Therefore a < g . (ii) When the coil is completely within the field, flux remains constant and hence no emf is induced. Therefore a = g . (iii) When the coil is coming out from the field, flux decreases and from Lenz's law the induced emf or current opposes the change. Therefore a < g .