Variation of magnetic field through a coil of area 4 m2 is shown in figure. What is the EMF induced in the coil (in mV)?
A coil of area A and N turns is rotating with angular velocity \( \omega\) in a uniform magnetic field \(\vec{B}\) about an axis perpendicular to \( \vec{B}\) Magnetic flux \(\varphi \text{ and induced emf } \varepsilon \text{ across it, at an instant when } \vec{B} \text{ is parallel to the plane of the coil, are:}\)

A conducting bar moves on two conducting rails as shown in the figure. A constant magnetic field \( B \) exists into the page. The bar starts to move from the vertex at time \( t = 0 \) with a constant velocity. If the induced EMF is \( E \propto t^n \), then the value of \( n \) is _____. 
There are two laws, given by Faraday which explain the phenomena of electromagnetic induction:
Whenever a conductor is placed in a varying magnetic field, an emf is induced. If the conductor circuit is closed, a current is induced, known as the induced current.
The Emf induced inside a coil is equal to the rate of change of associated magnetic flux.
This law can be mathematically written as:
∈\(-N {\triangle \phi \over \triangle t}\)
