PHYSICS CH 2 EXAM
Which of the following statements is correct?
Moving electrons constitute electric currents.
Which of the following statements is not true?
Protons and electrons have equal masses.
Which of the following is not true of molecular motion in a gas?
There is a definite average direction of motion at a given temperature.
An example of a wave that is partly longitudinal and partly transverse is a
Water wave
A magnet does not exert a force on
a stationary electric charge
The electrons in an atom
are some distance away from the nucleus
The pressure at the bottom of a barrel filled with liquid does not depend on the
area of the liquid surface.
When a magnetized iron bar is strongly heated, its magnetic field
becomes weaker
Light of which of the following colors is scattered most in the atmosphere?
blue
The Swedish flag is blue and yellow. When viewed with blue light it appears
blue and black
In order to operate, a heat engine must have
both a hot and a cold reservoir.
Heat transfer in a vacuum
can take place only by radiation.
The nucleus of an atom
contains most of the atom's mass.
The properties of several different materials are being compared. If the samples all have the same volume, the one with the greatest mass also has the greatest
density
Which of the following quantities is independent of the size and shape of an object composed of a given material?
density
The entropy of a system is a measure of its
disorder
A current is flowing south along a power line. Neglecting the earth's field, the direction of the magnetic field under the power line is
east
The conventional unit of battery capacity is the ampere-hour, which is actually a unit of
electric charge
Atoms and molecules are normally
electrically neutral.
When waves go from one place to another, they carry
energy
When a sound wave goes from air into water, the quantity that remains unchanged is its
frequency
Molecules are, in general, farthest apart from one another in
gases
Of the following, a molecule is best described as
he smallest particle of a substance that is representative of the substance
Heat transfer by conduction occurs
in liquids, solids, and gases
A negative electric charge
interacts with both positive and negative charges
Coulomb's formula F = KQ1Q2/R2 gives the force between two charges in free space. The value of K
is the same under all circumstances.
When a liquid freezes to become a solid,
it gives off heat
An object has a positive electric charge whenever
it has a deficiency of electrons
Ice floats in water because
its density is less than that of water.
When heat is added to a body of matter, the resulting temperature increase does not depend upon
its shape
You are looking at the bottom of a lake 1.2 m deep from a boat. To you the lake seems to be
less than 1.2 m deep
A cake of soap is placed in a bathtub sink. The buoyant force on the soap is
less than its weight.
A compass needle tends to
line up parallel to a magnetic field
The amplitude of a sound wave determines its
loudness
In order for an object to sink when placed in water, the object's average density must be
more than that of water
The pressure on the bottom of an object inside a liquid is
more than the pressure on its top.
The current with which a transformer is used
must be ac
Heat transfer by convection occurs
only in liquids and gases
In a transverse wave, the individual particles of the medium move
perpendicular to the direction of travel.
A molecule that has lost an electron becomes a
positive ion
When the American flag is viewed with red light it appears
red and black
The setting sun appears red because its light is
scattered
Sound waves travel fastest in
solids
A magnet attracts
some substances and repels others.
An example of a purely longitudinal wave is a
sound wave
When a gas is forced into a smaller volume without a change in temperature, its pressure increases because its molecules
strike the container walls more often.
A sample of a gas is expanded to twice its original volume while its temperature is held constant. Relative to their original average energy, the new average energy of the molecules is
the same
The higher the frequency of a wave,
the shorter its wavelength
Direct electric current cannot be used to operate
transformers
Relative to the electric force between two protons, the gravitational force between them is
weaker
An absolute temperature of 100 K is the same as a Celsius temperature o
-173°C
Molecular motion in a gas is the minimum possible at
0 K
The specific heat of water is 4.2 kJ/kg°C. The heat needed to warm 8 kg of water from 20°C to 70°C is
1680 kJ.
The current in a 24-W, 12-V light bulb is
2 A
The density of brass is 8 × 103 kg/m3. The volume occupied by 320 g of brass is
38 cm3
The primary coil of a transformer has 200 turns and its secondary coil has 40 turns. If the current in the secondary coil is 25 A, the current in the primary coil is
5 A
A temperature of 20°C is the same as
68°F
Ethanol boils at 172°F. The Celsius equivalent of this temperature is
78°C
The amplitude of the wave shown in the figure is
B
The wavelength of the wave shown in the figure is
D