Lenz's Law — Practice Quiz

Question 1

A bar magnet's N-pole approaches a stationary coil. The end of the coil facing the magnet becomes:

Accepted Answer

N-pole (repels)

Answer

S-pole (attracts)

Answer

Unmagnetised

Answer

Reverses each cycle

Question 2

Lenz's law is a consequence of:

Accepted Answer

Conservation of energy

Answer

Newton's third law

Answer

Conservation of charge

Answer

Maxwell's first equation

Question 3

When a magnet is pulled AWAY from a coil, the induced current:

Accepted Answer

Creates a field that opposes the motion (attracts the magnet back)

Answer

Vanishes immediately

Answer

Speeds the magnet up

Answer

Reverses many times

Question 4

Eddy currents are minimised in transformer cores by:

Accepted Answer

Using thin laminated iron sheets insulated from each other

Answer

Using copper laminations

Answer

Cooling the core

Answer

Reducing operating frequency

Question 5

A magnet is dropped into a vertical copper tube. Compared to free-fall, the descent is:

Accepted Answer

Much slower (Lenz-law braking)

Answer

Faster

Answer

Same

Answer

Bounces