Q 12-06-147JEE MainJEE Main 2017 (2 Apr)Easy
In a coil of resistance $100\ \Omega$, a current is induced by changing the magnetic flux through it as shown in the figure. The magnitude of change in flux through the coil is:
Answer: (D) $250$ Wb
The induced current is $I = \dfrac{\varepsilon}{R} = \dfrac{1}{R}\dfrac{d\phi}{dt}$ in magnitude, so
$$\Delta\phi = R\int I\,dt = R\times(\text{area under the } I\text{–}t \text{ graph})$$
$$\Delta\phi = 100\times\frac12\times10\times0.5 = 250\ \text{Wb}$$
Solution by Sreeraj P, M.Sc Physics