A conducting circular loop is placed in a uniform magnetic field of 0.04 ~T with its plane perpendicular to the magnetic field. The radius of the loop starts shrinking at 2 ~mm / s . The induced emf in the loop when the radius is 2 ~cm is

Step-by-step solution

Induced emf in the loop is given by e =- B d A dt where A is the area of the loop. array l e =- B d dt ( r ² )=- B 2 r dr dt r =2 ~cm =2 10⁻² ~m dr =2 ~mm =2 10⁻³ ~m dt =1 ~s e =-0.04 3.14 2 2 10⁻² 2 10⁻³ 1 ~V =0.32 10⁻⁵ ~V =3.2 10⁻⁶ ~V =3.2 V array