A horizontal copper loop is due east of, at the same elevation as, a straight horizontal wire carrying a steady current due north. What is the direction of the current induced to flow in the loop by the steady current in the wire?

a) Upward.

b) Downward.

c) Clockwise as viewed from above.

d) Counterclockwise as viewed from above.

e) There is no current induced in the loop by the steady current in the wire.

f) None of the above.

What is the purpose of transformers?

a) To step AC voltage up.

b) To step AC voltage down.

c) To convert AC to DC.

d) To convert DC to AC.

e) To convert Electrical Energy to Mechanical Energy.

f) To convert Mechanical Energy to Electrical Energy.

g) Both a and b.

h) Both c and d.

i) Both e and f.

Do transformers work with AC or DC?

a) AC.

b) DC.

c) Neither.

d) Both.

How does a transformer work?

a) A changing current through one coil causes creates a magnetic field through a second coil which is changing because the current through the first coil is changing. This changing magnetic field through the second coil induces a current in the second coil.

b) A current through one coil creates a magnetic field through a second coil which causes a current in the second coil.

c) A changing magnetic field causes a magnet to spin.

In a transformer, is it the current in the primary that causes the primary coil’s magnetic field or is it the changing of the current in the primary that causes the primary coil’s magnetic field?

a) The current itself.

b) The changing of the current.

In a transformer, is it the magnetic field through the region encircled by the secondary that causes the current in the secondary, or, is it the changing of that magnetic field that causes the current in the secondary?

a) The magnetic field itself.

b) The changing of the magnetic field.

Which of the following is a better description of a generator?

a) A spinning magnet near a coil that induces current to flow in that coil.

b) A changing current in a coil that causes a nearby magnet to spin.

What is the purpose of a generator?

a) To convert mechanical energy into electrical energy.

b) To convert electrical energy into mechanical energy.

c) To spin a magnet.

In a generator, what spins the magnet?

a) The changing magnetic field due to the current in the coil.

b) It varies. Steam engines, water turbines, diesel engines and other devices are used to spin magnet.

A long straight vertical wire carries an increasing current straight upward. Right beside the wire is a horizontal conducting loop. Which way is current induced to flow in the loop by the changing magnetic field of the wire?

a) Upward.

b) Downward.

c) Clockwise as viewed from above.

d) Counterclockwise as viewed from above.

e) There is no current induced in the loop.

f) None of the above.

A horizontal copper loop is due east of, at the same elevation as, a straight horizontal wire carrying a decreasing current due north. What is the direction of the current induced to flow in the loop by the changing current in the wire?

a) Clockwise as viewed from above.

b) Counterclockwise as viewed from above.

c) There is no current induced in the loop.

d) None of the above.