Question

The magnitude of induced emf is directly proportional to the rate of change of __________ linked with the circuit.

Answer 1

According to Faraday's law of electromagnetic induction, magnitude of induced emf is directly proportional to the rate of change of magnetic flux linked with the circuit.
Magnitude of induced emf $|E|=\frac{d\varphi }{dt}$
where $\varphi$ is the magnetic flux.