Download Electric Transformers Quiz Answer Key

Electric Transformers Quiz Answer Key
1. An electric transformer is a device that changes the _____ of electric current.
voltage
2. The process used by the device in question 1 is called electromagnetic _____.
induction
3. Define the process in question 2.
Electromagnetic induction is the process of generating electric current with a magnetic
field.
4. True or false: Electric transformers may either increase or decrease voltage.
true
5. An electric transformer contains
a) a single electric circuit.
b) an iron core.
c) a permanent magnet.
d) all of the above
b
6. An electric transformer creates an electromagnet when
a) alternating current passes through the secondary coil.
b) the magnetic field of the iron core keeps changing.
c) direct current passes through the primary coil.
d) none of the above
d
1
7. A transformer that increases voltage is called a(n) _____ transformer.
step-up
8. True or false: The type of transformer in question 7 would be found on an electric pole
outside of a home.
false
9. Electromagnetic induction occurs in an electric transformer because the
a) magnetic field keeps reversing.
b) secondary coil keeps moving.
c) primary coil keeps moving.
d) two of the above
a
10. An electric transformer works only with alternating current. Explain why.
Electromagnetic induction generates current in the secondary coil of wire in the
transformer. This occurs because the magnetic field of the iron core keeps reversing. The
magnetic field keeps reversing because it is caused by alternating current in the primary
coil of wire. If the current in the primary coil was direct current instead of alternating
current, the iron core would not have a magnetic field, let alone a constantly reversing
magnetic field. As a result, current would not be induced in the secondary core and the
transformer would not work.
2