Physical science homework 4
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
A current is flowing south along a power line. Neglecting the earths field, the direction of the magnetic field under the power line is
East
A kilowatt hour is a unit of
Energy
When waves go from one place to another, they carry
Energy
When a sound wave goes from air to water, the quantity that remains unchanged is its
Frequency
Heat transfers by convection occurs
In liquids, gases, and solids
Heat transfers by conduction occurs
In liquids, solids, and gases
Atoms and molecules are normally
Ionized
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
Sublimation refers to
It gives off heat
When a liquid freezes to become a solid
It gives off heat
Ice floats in water because
It is colder than water
Where's the amplitude of a wave
It's the line that goes up and down in between the waves
When heat is added to a body of matter, the resulting temperature increases does not depend upon
Its shape
The first law of thermodynamics is the same as the
Law of conservation of energy
A compass needle tends to
Line up parallel to a magnetic field
In order for an object to sink when placed in water, the objects 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
Which of the following statements is correct
Moving electrons constitute electric currents
In a transverse wave, the individual particles of the medium move
Perpendicular to the direction of travel
Which of the following effects does not occur in all types of wave
Polarization
The volt is the unit of electric
Potential difference
The setting sun appears red because it's light is
Scattered
Sound waves travel faster in
Solids
An example of a purely longitudinal wave is a
Sound wave
Where's the wavelength of the wave
The line on the bottom showing how long it is from the bottom of the wave to the top of the wave
A current-carrying wire is in a magnetic field with the direction of the current perpendicular to that of the field
The wire tends to move perpendicular to the field
An example of a wave that is partly longitudinal and partly transverse is a
Water wave
A barometer measures
atmospheric pressure
A negative electric charge
interacts with both positive and negative charges
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
The current with which a transformer is used
must be ac
A magnet attracts
some substances and repels others
Dispersion is the term used to describe the
splitting of white light into its component colors in refraction
Of the substances below, the one with the highest specific heat is
water
Molecular motion in gas is the minimum possible at
0 k
The current in a 20-ohm electric heater operated at 240 V is
12 A
The speed of light in a transparent plastic whose index of refraction is 1.5 is
2 x 10^8 m/s
The primary coil of a transformer has 200 turns and it's secondary coil has 50 turns and the current in the secondary coil is 40 A. When a 12-V alternating current is applied to the primary coil of the transformer the secondary voltage will be
3 V
A transformer used to reduce 240-V ac to 120-V ac has an input current of 15 A. Its output current is
30
The density of brass is 8 × 103 kg/m3. The volume occupied by 320 g of brass is
38cm^3
A temperature of 20°C is the same as
68°F
A changing electric field gives rise to
A magnetic field
A magnet does not exert a force on
A stationary electric charge
The pressure at the bottom of a barrel filled with liquid does not depend on the
Area of the liquid surface
When a current passes through a resistance, the electric energy that is lost
Becomes heat
When a magnetized iron bar is strongly heated, it's magnetic field
Becomes weaker
The nucleus of an atom
Contains most of the atoms mass