• # question_answer In the graph variation of magnetic field with time 't' applied perpendicular to the plane of the ring is shown: A) at $t=2\sec$and current flowing in ring is equal to zero B) current will change its direction two times in time intervals $t=0$ to $t=8\,\,\sec$ C) current will change its direction only once in the above interval D)  flux in ring is same at $t=0$ & $t=4\,\,\sec .$

 For $t=0$ to $t=4:\frac{dB}{dt}$ is negative, and for $t=4$ to $t=8:\frac{dB}{dt}$is positive. $\therefore$      sign of current will change only once.