JEE Main202127 Aug 2021Evening ShiftPhysicsElectromagnetic InductionActual
A constant magnetic field of 1 T is applied in the x > 0 region. A metallic circular ring of radius 1 m is moving with a constant velocity of 1 m s - 1 along the x -axis. At t = 0 s , the centre O of the ring is at x = - 1 m . What will be the value of the induced emf in the ring at t = 1 s ? (Assume the velocity of the ring does not change.)
Options
- A0   V
- B2   V
- C2 π   V
- D1   V
Correct answer
B. 2   V
Step-by-step solution
Recall the formula of induced E.M.F. in terms of the length of the rod, and uniform magnetic field, E = B v l , here in the case of the ring, l = 2 R , ⇒ E = B v 2 R , when half ring enters, E = 1 × 1 × 2 × 1 = 2   V .