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