Physics Final

A heater uses 20 A when used in a 110-V line. If electric power costs 10 cents per kilowatt hour, the cost of running the heater for 10 hours is

$2.20.

Two charges separated by one meter exert 1-N forces on each other. If the charges are pulled to 3-m separation distance, the force on each charge will be

0.11 N.

A weight or mass on the end of a spring bobs up and down one complete cycle every two seconds. Its frequency is

0.5 hertz.

If you use 10 J of work to push a charge into an electric field and then release the charge, as it flies past its starting position, its kinetic energy is

10 J

A power line with a resistance of 2 ohms has a current of 80 A in it. The power dissipated in the line is

12,800 W.

A floating leaf oscillates up and down two complete cycles each second as a water wave passes by. What is the wave's frequency?

2 hertz

A volume of air has a temperature of 0 degrees Celsius. An equal volume of air that is twice as hot has a temperature of

273 degrees C.

Two identical blocks of iron, one at 10 degrees C and the other at 20 degrees C, are put in contact. Suppose the cooler block cools to 5 degrees C and the warmer block warms to 25 degrees C. This would violate the

2nd law of thermodynamics.

A skipper on a boat notices wave crests passing the anchor chain every 5 seconds. The skipper estimates the distance between crests is 15 m. What is the speed of the water waves?

3 m/s

The mass of ice that can be melted by 1 gram of 100-degree-C steam is

8 grams

If we think of the Earth as a magnet, its north (-seeking) pole is nearest

Australia.

Stored potatoes, beets, and rutabagas freeze at temperatures below zero degrees Celsius (rather than AT zero) because

The water in them contains dissolved salts and sugars.

The unit of electric charge, the coulomb, is the charge on

a specific large number of electrons.

A standing wave occurs when

a wave reflects upon itself.

The pupil of your eye is a net

absorber of radiant energy.

A substance can absorb heat energy by the process of

all of these.

The sonic boom at ground level produced by an aircraft will be reduced if the aircraft

all of these.

Wave interference occurs for

all of these.

If you were caught in freezing weather with only a candle for heat, you would be warmer in

an igloo.

A wave barrier is produced when a wave source moves

as fast as the waves it produces.

Pour a liter of water at 40 degrees C into a liter of water at 20 degrees C and the final temperature of the two becomes

at or about 30 degrees C.

If a steady magnetic field exerts a force on a moving charge, that force is directed

at right angles to the direction of the motion.

The vibrations of a transverse wave move in a direction

at right angles to the direction of wave travel.

The source of electrons lighting an incandescent ac light bulb is

atoms in the light bulb filament.

An uncharged pith ball is suspended by a nylon fiber. When a negatively charged rubber rod is brought nearby, without touching it, the pith ball

becomes polarized.

Consider a metal ring with a gap cut in it. When the ring is heated, the gap

becomes wider.

Charges on the plates of a charged capacitor reside on the surfaces

between the capacitor plates.

Cold water will warm to room temperature faster in a

black pot.

A quantity of water has more entropy when it is

boiling.

Surrounding every moving electron is

both of these.

An electrical diode is useful for

changing the ac to dc

The electrical force between charges is strongest when the charges are

close together

Consider a steaming aluminum soda-pop can that contains a small amount of boiling water. When it is quickly inverted into a bath of cooler water the can is dramatically crushed by atmospheric pressure. This occurs because the pressure inside the can is rapidly reduced by

condensation of steam inside.

The first law of thermodynamics is a restatement of the

conservation of energy.

Melting snow

cools the surrounding air.

Sue's refrigerator is built into the wall of her kitchen, so that it exhausts heat to the outdoors rather than into the room. If Sue tries to cool her kitchen by leaving the refrigerator door open, the room temperature will

decrease at least slightly.

When a volume of air is compressed and no heat enters or leaves, the air temperature will

decrease.

As a piece of metal with a hole in it cools, the diameter of the hole

decreases

As more lamps are put into a series circuit, the overall current in the power source

decreases.

Consider a sample of water at 0 degrees C. If the temperature is slightly increased, the volume of the water

decreases.

Which force binds atoms together to form molecules?

electrical

In an electrically neutral atom the number of protons in the nucleus is equal to the number of

electrons that surround the nucleus.

You can touch a 100,000-volt Van de Graaff generator with little harm because although the voltage is high, the relatively small amount of charge means there is a relatively small amount of

energy.

Compared to the huge force that attracts an iron tack to a strong magnet, the force that the tack exerts on the magnet is

equally huge.

When you touch a cold piece of ice with your finger, energy flows

from your finger to the ice.

For increased atmospheric pressure, the boiling temperature of a liquid

goes up.

A good absorber of radiation is a

good emitter of radiation.

Which of the following contracts most when the temperature is increased? Equal volumes of

helium.

Compared to a giant iceberg, a hot cup of coffee has

higher temperature, but less internal energy.

Heat a copper wire and its electric resistance

increases.

Which of the following normally warms up fastest when heat is applied?

iron

Magnetic domains normally occur in

iron.

Hydrogen and oxygen molecules in a gas sample have the same temperature. This means the hydrogen molecules, on the average, have the same

kinetic energy, but more speed.

Compared to a single lamp connected to a battery, two identical lamps connected in series to the same battery will carry

less current.

Compressions and rarefactions are characteristic of

longitudinal waves.

The frequencies of sound that carry farther in air are relatively

low

Which force field can accelerate an electron, but never change its speed?

magnetic field

To turn 50 grams of boiling water to steam requires

more calories than are required to bring 50 grams of ice at absolute zero to the boiling point.

Systems that are left alone, tend to move toward a state of

more entropy.

If the specific heat of water were lower than it is, ponds in the cold of winter would be

more likely to freeze.

A 10-ohm resistor has a 5-A current in it. What is the voltage across the resistor?

more than 20 V

When two lamps are connected in series to a battery, the electrical resistance that the battery senses is

more than the resistance of either lamp.

Rub electrons from your hair with a comb and the comb becomes

negatively charged

Food cooked in boiling water in the mountains cooks slower than when cooked at sea level. If the temperature under the pot is increased, the food will cook

neither of these

Heating the Earth's atmosphere is caused by energy

neither of these. (?)

The electric field around an isolated electron has a certain strength 1 cm from the electron. The electric field strength 2 cm from the electron is

none of these (1/4)

When an ideal gas is subjected to an adiabatic process

none of these.

An iron nail is more strongly attracted to the

north or south pole - no difference really.

Which pole of a compass needle points to a south pole of a magnet?

north pole

Outside a magnet, magnetic field lines are conventionally drawn from

north to south.

Two charged particles held close to each other are released. As the particles move, the velocity of each increases. Therefore, their charges have

opposite signs.

The force on an electron moving in a magnetic field will be the largest when its direction is

perpendicular to the magnetic field direction.

The intensity of cosmic rays bombarding the Earth's surface is largest at the

poles.

A good heat conductor is a

poor insulator

Wrapping a hot potato in aluminum foil significantly reduces the rate at which it loses energy by

radiation

When liquids change to a solid state, they

release energy.

A difference between electric forces and gravitational forces is that electrical forces include

repulsive interactions

In an electric circuit, the safety fuse is connected to the circuit in

series.

The pendulum with the greatest frequency is the pendulum with the

shortest length.

Morning dew on the grass is a result of

slow-moving water molecules sticking to one another.

The explanation for refraction must involve a change in

speed.

Firefighters find that the temperature of burning material is best lowered when water is

sprayed as a fine mist

When heat is added to boiling water, its temperature

stays the same.

Sound travels faster in

steel.

A 60-W light bulb and a 100-W light bulb are each connected to a 120 V outlet. Which light bulb has more current in it?

the 100-W bulb

The speed of a sound wave in air depends on

the air temperature.

Both black and white road surfaces radiate energy. At the end of a starry night the warmer road surface will be

the black surface.

The white-hot sparks that strike your skin from a 4th-of-July-type sparkler don't harm you because

the energy per molecule is high, but little energy is transferred because of the few molecules in the spark.

Evaporation is a cooling process because

the more energetic molecules are able to escape the liquid.

An iron rod becomes magnetic when

the net spins of its electrons are in the same direction.

In a longitudinal wave the compressions and rarefactions travel in

the same direction.

Two lamps, one with a thick filament and one with a thin filament, are connected in series. The current is greater in the lamp with the

the same in each lamp.

A hot dog pants

to help evaporation occur in its mouth and bronchial tract.

A Doppler effect occurs when a source of sound moves

toward you.

If you plug an electric toaster rated at 110 V into a 220-V outlet, the current in the toaster will be about

twice what it should be.

At the same temperature, which move with the greater speed in the air?

very light molecules

The source of every sound is something that is

vibrating.

If a volume of air is warmed, it expands. If a volume of air expands, it

warms.

When a car is struck by lightning, the resulting electric field inside the car is

zero