question_answer

The graph gives the magnitude B(t) of a uniform magnetic field that exists throughout a conducting loop, perpendicular to the plane of the loop. Rank the five regions of the graph according to the magnitude of the emf induced in the loop, greatest first

A)            b > (d = e) < (a = c)                   

B)            b > (d = e) > (a = c)                                                                

C)            b < d < e < c < a

D)            b > (a = c) > (d = e)            

Correct Answer: B

Solution :

                   Induced emf \[e=A\frac{dB}{dt}\]                    i.e. \[e\propto \frac{dB}{dt}\](= slope of B ? t graph)    In the given graph slope of AB > slope of CD, slope in the ?a? region = slope in the ?c? region = 0, slope in the?d? region = slope in the ?e? region \[\ne 0\]. That?s why \[b>(d=e)>(a=c)\]