Physical Science Chapter 17 Practice Test #2

Multiple Choice

Identify the letter of the choice that best completes the statement or answers the question.

____ 1. An example of a naturally occurring magnetic rock is

a. / lodestone. / c. / limestone.
b. / soapstone. / d. / peastone.

____ 2. Magnetically soft substances

a. / retain their magnetism longer than others.
b. / lose their magnetism more easily than others.
c. / cannot be magnetized easily.
d. / pick up more iron nails than magnetically hard substances.

____ 3. Like magnetic poles always

a. / repel each other. / c. / cancel out each other’s magnetic fields.
b. / attract each other. / d. / point toward the north pole.

____ 4. The magnetism of a piece of magnetized iron can be weakened by

a. / heating and hammering the iron. / c. / bending the iron.
b. / touching unmagnetized iron. / d. / None of the above

____ 5. The magnetic field strength of a magnet

a. / decreases as distance from the magnet decreases.
b. / decreases as distance from the magnet increases.
c. / increases as distance from the magnet increases.
d. / remains the same at any distance from a magnet.

____ 6. What material was used to make the first compass?

a. / lodestone / c. / iron
b. / limestone / d. / steel

____ 7. What instrument is used to trace the direction of a magnetic field?

a. / lodestone / c. / compass
b. / limestone / d. / needle

____ 8. What causes a compass needle to point to geographic north?

a. / The pole of the compass is attracted to Earth’s Geographic North Pole.
b. / The compass needle aligns with Earth’s magnetic field.
c. / The force of Earth’s rotation causes the needle of the compass to seek the north pole.
d. / All of the above

____ 9. Where are Earth’s magnetic poles are located?

a. / Canada and Australia / c. / Canada and Antarctica
b. / Canada and Alaska / d. / at the geographic poles

____ 10. Magnetic fields are produced by

a. / electric charges. / c. / gravitational force.
b. / electric currents. / d. / water currents.

____ 11. A magnetic field around a current-carrying wire forms

a. / lines tangent to the wire. / c. / lines parallel to the wire.
b. / lines perpendicular to the wire. / d. / concentric circles around the wire.

____ 12. The strength of a magnetic field created by current in a wire can be increased by

a. / using shorter wire. / c. / using longer wire.
b. / decreasing the current in the wire. / d. / wrapping the wire into a coil.

____ 13. The strength of the magnetic field of a solenoid can be increased by

a. / decreasing the number of loops on the solenoid.
b. / decreasing the current in the solenoid.
c. / increasing the number of loops on the solenoid.
d. / increasing the resistance of the solenoid.

____ 14. The strength of the magnetic field of a solenoid can be increased by

a. / decreasing its number of loops. / c. / inserting an iron rod.
b. / decreasing its current. / d. / inserting a rubber rod.

____ 15. In a magnetized substance, the domains

a. / are randomly distributed. / c. / cancel each other.
b. / line up more uniformly in one direction. / d. / can never be reoriented.

____ 16. Which orientation characterizes the magnetic domains in an unmagnetized piece of iron?

a. / parallel to the magnetic axis / c. / random
b. / antiparallel to the magnetic axis / d. / perpendicular to the magnetic axis

____ 17. A device that converts electric energy into mechanical energy is a(n)

a. / generator. / c. / commutator.
b. / electric motor. / d. / transformer.

____ 18. A potential difference causes

a. / electrons to move from the positive terminal to the negative terminal of a battery.
b. / electrons to move from the negative terminal to the positive terminal of a battery.
c. / protons to move from the positive terminal to the negative terminal of a battery.
d. / protons to move from the negative terminal to the positive terminal of a battery.

____ 19. When a charge moves along or opposite the direction of the magnetic field lines, the magnetic force is

a. / zero.
b. / a maximum.
c. / equal to the magnetic force when it moves perpendicular to the magnetic field lines.
d. / None of the above

____ 20. When a wire is moving perpendicular to a magnetic field, the force on the charges is

a. / at a minimum. / c. / zero.
b. / at a maximum. / d. / All of the above

____ 21. Generators convert

a. / mechanical energy to electrical energy. / c. / chemical energy to electrical energy.
b. / electrical energy to mechanical energy. / d. / electrical energy to chemical energy.

____ 22. A transformer changes

a. / both the amperage and the voltage of an electric current.
b. / the voltage of an electric current.
c. / the amperage of an electric current.
d. / the type of an electric current.

Short Answer

23. Will the magnets in the figure attract or repel each other?

24. What do magnetic field lines that are close together indicate?

25. A current-carrying wire is perpendicular to the surface of a table. The direction of current is toward the floor. What is the direction of the magnetic field as viewed from above?

26. What is a generator?

27. How are generators different from electric motors?

28. What are step-up and step-down transformers used for?