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