A square loop is pushed into a narrow region of magnetic fie

A square loop is pushed into a narrow region of magnetic field of strength B = 0.20 T at a speed of v = 50 m/s. The resistance of the loop is R = 0.10 Ohm. The three drawings below show the following: A) The loop entering the magnetic field B) the loop moving after it has fully entered the field C) The loop leaving the field. A) What is the magnitude and direction of the induced current in the loop when it is entering the magnetic field? Clearly show your work and explain. B) What is the magnitude and direction of the induced current in the loop after it has fully entered the magnetic field? Clearly show your work and explain.

Solution

(A).Magnetic field B = 0.2 T

Length of the loop L = 5 cm = 0.05 m

Resistance R = 0.1 ohm

Speed v = 50 m/s

Induced emf E = BLv

                     = 0.2 x 0.05 x50

                     = 0.5 volt

Induced current i = E / R

                         = 0.5 volt / 0.1 ohm

                         = 5 A

Magnitude of induced current = 5 A

According to Lenz\'s law the direction of induced current is opposite to the direction of change in magnetic flux.

Here the change in magnetic flux is in right direction.So, the direction of induced current is along counter clock wise direction.

(B).After fully enter into the magnetic filed ,the change in magnetic flux is zero.Therefore there is no induced current in the loop.