Q.Mention the ways of producing induced emf.

The three routes. Faraday's basic formula, $\varepsilon=-d\Phi_B/dt$ with $\Phi_B=BA\cos\theta$, shows an emf can be produced by changing ANY of the three factors that build up the flux: the field strength B, the enclosed area A, or the relative orientation angle $\theta$.

1. Changing the magnetic field. This is the mechanism behind BOTH of Faraday's original experiments -- relative motion between a magnet and a stationary coil changes the field strength linking the coil as the magnet approaches or recedes; a changing current in a nearby primary coil changes the field it produces, inducing an emf in a neighbouring secondary coil. In both cases the circuit's own area and orientation stay fixed throughout.
2. Changing the area (developed fully under Inducing EMF by Changing Area) -- a conducting rod sliding along a fixed frame continuously changes the enclosed loop area even though B itself never changes, giving the motional emf $\varepsilon=Blv$. …