Electromagnetic Induction problems

Faraday’s Law

1. (a) A coil of radius 20 cm consisting of 20 turns is held 2 meters above the south

end of a magnet. If the coil is dropped, determine the average induced EMF

(voltage) once the loop hits the magnet if the field strength at the 2 m height

is 0.005 T, and is 0.01 T at the surface of the magnet.

(b) What is the direction of the induced current, as seen from above the coil?

2..

A square loop of copper coil 10 cm on each side is in static magnetic field of

0.005 T perpendicular to the loop. The coil is deformed into a circle having the

same circumference as the square loop. If this shape-change occurs in 5 seconds,

and the coil has a resistance of 1 , determine the induced current in the coil.

3. A 100 turn conducting circular coil of radius 1 cm is placed in a magnetic field

of variable.

3. A 100 turn conducting circular coil of radius 1 cm is placed in a magnetic field

of variable strength B(t) = 0.01t + 0.01 Tesla, which is perpendicular to the

plane of the loop. Determine the induced EMF.

Lenz’s Law

When an emf is generated by a change in magnetic flux according to Faraday's Law, the polarity or direction of the induced emf is such that it produces a current whose magnetic field opposes the change which produces it.