A square-shaped copper coil has edges of length 50 cm and contains 50 turns. It is placed perpendicular to a 1.0T magnetic field. It is removed from the magnetic field in 0.25 s and restored in its original place in the next 0.25 s. Find the magnitude of the average emf induced in the loop during
(a) its removal, (b) its restoration and (c) its motion.
Given:
Length of side of square=
No. of turns=50
Intensity of magnetic field =1.0T
Average induced emf in time interval Δt is given by
…(i)
Where
are flux across the cross section at time intervals 
respectively.
Magnetic flux due to magnetic field B through cross section area A is given by
(a) During removal
Initial magnetic flux through the loop
Final magnetic flux through the loop
Time interval Δt=0.25s
Using eqn.(i) we get
Magnitude of average emf during removal is 50V
(b) During restoration
Initial magnetic flux through the loop
Final magnetic flux through the loop
Time interval Δt=0.25s
Using eqn.(i) we get
Magnitude of average emf during restoration is 50V
(c) During the motion
Initial magnetic flux through the loop
Final magnetic flux through the loop
Time interval Δt=0.25+0.25=0.50s
Using eqm. (i) we get
Therefore, magnitude of average emf during its motion is zero