Question

Consider a standalone solenoid and answer the following questions.

a) If a bar magnet is introduced into the solenoid at a constant velocity, what effect will

this have on the solenoid?

b) How does the moving speed of the magnet affect the solenoid?

c) When the bar magnet is stationary inside the solenoid, what effect will this have on the solenoid?

d) The magnet is pulled out of the solenoid at the same speed as it was inserted; what

effect does this have on the solenoid?

Answer 1

a) As the magnet is introduced into the solenoid, the flux though the solenoid changes, this will induce a current (emf) in the solenoid.

b) The greater speed of the magnet produces greater change in the flux through the solenoid hence the induced emf in the solenoid is greater.

c) There will be no effect on the solenoid when the bar magnet is stationary.

d) Pulling out magnet will also change the flux through solenoid. Hence there will be an induced current in the solenoid but this

time opposite in direction.