Faraday's law states that when the magnetic flux through a loop of the conductor will change with respect to time, then the EMF will be generated across the ends of the conductor.

According to Faraday's law of electromagnetic induction,

$$\begin{gathered} \left|\epsilon \right|=\left|-\frac{d\varphi }{dt}\right| \\ \left|-\overrightarrow{E}·d\overrightarrow{r}\right|=\left|-A\frac{dB}{dt}\right| \end{gathered}$$ 

where, $A$ is the area of loop and $B$is the magnetic field.

Clearly, electric field is produced by time varying magnetic field.