JEE MainPhysicsElectromagnetic Induction
A small square loop of wire of side a is placed at the center of a large circular loop of wire of radius R ( a R ). The large loop carries a steady current I . The small loop is rotated about its diagonal, which lies along a diameter of the large loop, with a constant angular velocity . The maximum induced EMF in the small square loop is
Options
- A₀ I a^2 2 R
- B₀ I a^2 2R
- C₀ I a^2 2R
- D₀ I a^2 R
Correct answer
C. ₀ I a^2 2R
Step-by-step solution
The magnetic field at the center of the large circular loop carrying current I is: B = ₀ I 2R Since a R , the magnetic field is approximately uniform over the area of the small square loop. The area of the small square loop is A = a^2 . As the small loop rotates with angular velocity , the angle between the area vector of the loop and the magnetic field at time t is = t (assuming they are parallel at t=0 ). The magnetic flux linked with the small square loop at time t is: = B A ( t) = ( ₀ I 2R ) a^2 ( t) According