A square loop of side 2 ~cm enters a magnetic field with a constant speed of 2 ~cm ~s ⁻¹ as shown. The front edge enters the field at t=0 ~s . Which of the following graph correctly depicts the induced emf in the loop? (Take clockwise direction positive)

Step-by-step solution

As the loop moves, there are three cases. (i) When the loop moves fully outside the magnetic field, there is no change in flux. = d d t =0 (ii) When the loop is entering/leaving the area of magnetic field. gathered =B L V=(0.9) (2 10⁻² ) (2 10⁻² ) =2 10⁻⁴ ~V gathered As flux is in opposite direction to magnetic field. when loop enters the field =-2 10⁻⁴ ~V =2 10⁻⁴ ~V (iii) When moving inside the magnetic field. d d t =0 No emf is induced.