The scientist who first discovered a link between electricity and
magnetism is
a. Hans Oersted
b. Albert Einstein
c. Michael Faraday
d. William Gilbert
Which of the following is "not" a characteristic of a step-down
transformer?
a. There are fewer loops on the secondary coil than on the primary
coil.
b. It converts alternating current into direct current.
c. The voltage of the secondary coil is less than that of the
primary coil.
d. It is necessary for a doorbell to operate.
A step-up transformer is used in
a. tape players
b. calculators
c. doorbells
d. television sets
The best core for an electromagnet is
a. alnico
b. iron
c. aluminum
d. magnetite
Which of the following will "not" strengthen an electromagnet?
a. increasing the number of loops of wire around the core
b. increasing the current flow
c. decreasing the voltage
d. all of these
In order for a motor to run off direct current, it must contain a
a. glvanometer
b. U-shaped magnet
c. primary coil
d. commutator
The phenomenon in which a current is produced by a changing magnetic
field is called electromagnetic
a. conduction
b. transformation
c. induction
d. generation
Alternating current in the United States has a frequency of
a. 30 hertz
b. 60 hertz
c. 120 hertz
d. 240 hertz
Almost all of the electricity that people use is produced by
a. generators
b. motors
c. batteries
d. transformers
A step-down transformer is used in
a. doorbells
b. X-ray machines
c. fluorescent lights
d. television sets
