Assignment:
Part 1
Choose the BEST answer to each of the following.
1. A fire walker walking barefoot across hot wooden coals depends on wood's
(a) good conduction.
(b) poor conduction.
(c) low specific heat capacity.
(d) wetness.
2. Thermal convection is linked mostly to
(a) radiant energy.
(b) fluids.
(c) insulators.
(d) all of these
3. When air is rapidly compressed, its temperature normally
(a) increases.
(b) decreases.
(c) remains unchanged.
(d) is unaffected, but not always.
4. An object that absorbs energy well also
(a) conducts well.
(b) convects well.
(c) radiates well.
(d) none of these
5. Which of these electromagnetic waves has the lowest frequency?
(a) infrared
(b) visible
(c) ultraviolet
(d) gamma rays
6. Compared with terrestrial radiation, the radiation from the Sun has a
(a) longer wavelength.
(b) lower frequency.
(c) both of these
(d) none of these
7. Glass is transparent to short-wavelength light and is
(a) opaque to light of longer wavelengths.
(b) opaque to the same light that is reflected from an interior surface.
(c) both of these
(d) none of these
8. When evaporation occurs in a dish of water, the molecules left behind in the water
(a) are less energetic.
(b) have decreased average speeds.
(c) result in lowered temperature.
(d) all of these
9. When steam changes phase to water, it
(a) absorbs energy.
(b) releases energy.
(c) neither absorbs nor releases energy.
(d) becomes more conducting.
10. Boiling and freezing can occur at the same time when water is subjected to
(a) decreased temperatures.
(b) decreased atmospheric pressure.
(c) increased temperatures.
(d) increased atmospheric pressure.
Part 2
Choose the BEST answer to each of the following.
1. When we say charge is conserved, we mean that charge can
(a) be saved, like money in a bank.
(b) not be created or destroyed.
(c) be created or destroyed, but only in nuclear reactions.
(d) take equivalent forms.
2. When a pair of charged particles are brought twice as close to each other, the force between them becomes
(a) twice as strong.
(b) four times as strong.
(c) half as strong.
(d) one quarter as strong.
3. An electric field surrounds all
(a) electric charge.
(b) electrons.
(c) protons.
(d) all of these
4. Electric potential and electric potential energy are
(a) one and the same in most cases.
(b) two terms for the same concept.
(c) both of these
(d) neither of these
5. Which statement is correct?
(a) Voltage flows in a circuit.
(b) Charge flows in a circuit.
(c) A battery is the source of electrons in a circuit.
(d) All are correct.
6. When you double the voltage in a simple electric circuit, you double the
(a) current.
(b) resistance.
(c) both of these
(d) neither of these
7. If you double both the current and the voltage in a circuit, the power
(a) remains unchanged if the resistance remains constant.
(b) halves.
(c) doubles.
(d) quadruples.
8. In a simple circuit consisting of a single lamp and a single battery, when the current in the lamp is 2 A, the current in the battery is
(a) half, 1 A.
(b) 2 A.
(c) dependent on the internal battery resistance.
(d) not enough information to say
9. In a circuit with two lamps in parallel, if the current in one lamp is 2 A, the current in the battery is
(a) half, 1 A.
(b) 2 A.
(c) more than 2 A.
(d) not enough information to say
10. What is the power rating of a lamp connected to a 12-V source when it carries 2.5 A?
(a) 4.8 W
(b) 14.5 W
(c) 30 W
Part 3
Choose the BEST answer to each of the following.
1. The source of all magnetism is
(a) tiny bits of iron.
(b) tiny domains of aligned atoms.
(c) small lodestones.
(d) the motion of electrons.
2. Surrounding moving electric charges are
(a) electric fields.
(b) magnetic fields.
(c) both of these
(d) neither of these
3. A magnetic force acts most strongly on a current-carrying wire when the wire
(a) carries a very large current.
(b) is perpendicular to the magnetic field.
(c) either or both of these
(d) none of the above
4. A magnetic force acting on a beam of electrons can change
(a) only the direction of the beam.
(b) only the energy of the electrons.
(c) both the direction and the energy.
(d) neither the direction nor the energy.
5. When you thrust a bar magnet to and fro into a coil of wire, you induce
(a) direct current.
(b) alternating current.
(c) neither dc nor ac.
(d) alternating voltage only, not current.
6. The underlying physics of an electric motor is that
(a) electric and magnetic fields repel each other.
(b) a current-carrying wire experiences force in a magnetic field.
(c) like magnetic poles both attract and repel each other.
(d) ac voltage is induced by a changing magnetic field.
7. The essential physics concept in an electric generator is
(a) Coulomb's law.
(b) Ohm's law.
(c) Faraday's law.
(d) Newton's second law.
8. A transformer works by way of
(a) Coulomb's law.
(b) Ohm's law.
(c) Faraday's law.
(d) Newton's second law.
9. A step-up transformer in an electric circuit can step up
(a) voltage.
(b) energy.
(c) both of these
(d) neither of these
10. Electricity and magnetism connect to form
(a) mass.
(b) energy.
(c) ultra high-frequency sound.
(d) light.