A round loop of wire radius 02 m lies in a 5 T magnetic fiel

A round loop of wire (radius 0.2 m) lies in a 5 T magnetic field directed out of the page. The radius is increased to 0.3 m) in 2 seconds. What is the EMF produced and in which direction does the current flow?

Solution

emf produced = d(phi)/dt

=> phi = B*A =

=> emf induced = 3.14*(0.3^2-0.2^2)*5)/(2 = 0.392 V ,

currentwill flow clock wise to reduce the net flux