Eddy Currents (Magnetic Braking) — Practice Quiz

Question 1

Why are transformer cores LAMINATED rather than solid?

Accepted Answer

To reduce eddy-current losses

Answer

To reduce weight

Answer

To allow easier winding

Answer

To improve magnetic permeability

Question 2

A solid metal pendulum swings between magnet poles and quickly stops. The same pendulum with a SLOTTED bob continues swinging. The reason is:

Accepted Answer

Slots break the path of eddy currents, so damping disappears

Answer

Air resistance changed

Answer

Slots reduce mass

Answer

Magnetic field strength changes

Question 3

Induction cooktops heat a pan by:

Accepted Answer

Eddy currents and hysteresis losses in the ferromagnetic pan base

Answer

Microwave radiation

Answer

Infrared radiation

Answer

Direct conduction from a coil

Question 4

Eddy-current losses in a magnetic core depend on lamination thickness t as:

Accepted Answer

t²

Answer

1/t

Answer

t

Answer

t³

Question 5

Electromagnetic brakes on a high-speed train:

Accepted Answer

Use eddy currents induced in a rail or rotor to produce a retarding force

Answer

Use frictional pads pressed by magnets

Answer

Use magnetic monopoles

Answer

Are simply electromagnets attracting iron