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 :
$\varepsilon = \frac{d\phi}{dt}$ $ iR = \frac{d\phi}{dt} $ $\int d\phi = R \int idt $ Magnitude of change in flux = R $\times$ area under current vs time graph $ = 100 \times \frac{1}{2} \times \frac{1}{2} \times 10$ $= 250 \, Wb$
Electromagnetic Induction is a current produced by the voltage production due to a changing magnetic field. This happens in one of the two conditions:-
When we place the conductor in a changing magnetic field.
When the conductor constantly moves in a stationary field.