Q69 / 90 · JEE Main 2021 (01 Sep Shift 2) · Physics

A square loop of side 20 cm and resistance 1 Ω is moved towards right with a constant speed v0. The right arm of the loop is in a uniform magnetic field of 5 T. The field is perpendicular to the plane of the loop and is going into it. The loop is connected to a network of resistors each of value 4Ω. What should be the value of v0 so that a steady current of 2 mA flows in the loop ?

Figure

  • A
    10-2 cm s-1
  • B
    1 m s-1
  • Correct answer
    C
    1 cm s-1
  • D
    102 m s-1

Solution

The EMF is induced in the coil when it is moving in a uniform magnetic field,
e=Bvl and the current, i=eR⇒BlvR=0.002 A
 ⇒v=0.002×RBl=0.002×4+15×0.2=0.01 m s-1=1 cm s-1.

Hence, the correct answer is option: 'C'.

Relevant Questions