Question

ADC is a semi-circular loop of conducting wire of radius r and centred at O. The initial position of the loop with respect to the magnetic field is shown in fig 1. The loop is then pulled into the magnetic field (fig 2.) and makes two complete rotations about point O. 

(a) Plot a graph between the induced current I and the angle of rotation θ for two complete periods of rotations. 

(b) Depict the above graph in case the loop ADC revolves with angular frequency ω’ > ω. Keep all other conditions fixed as earlier. Give a reason for the change depicted in the graph.

Answer 1

(a) The graph between I and angle of rotation θ when the loop revolves with angular frequency ω : 

 

(b) The graph between I and angle of rotation θ when the loop revolves with higher angular frequency ω’ : 

Reason : As angular frequency increases, the rate of change in the flux linked with the loop increases. This increases the induced emf and hence the corresponding value of the induced current also increases.