EPS EXAM #2

The lowest temperature possible in nature is

-273°C

Two charges separated by 1 m exert a 1-N force on each other. If the charges are pulled to a3-m separation distance, the force on each charge will be

0.11 N

It is possible to totally convert a given amount of mechanical energy into heat.

True

In the mountains, water boils at

a lower temperature than at sea level.

Electrons are made to flow in a wire when there is

a potential difference across its ends.

The pupil of your eye is designed to be an

absorber of radiant energy

When a solid is changed to a liquid phase, the solid

absorbs energy

Surrounding every moving electron is

an electric field and a magnetic field

Rapid changes of a magnetic field induces

an electric field.

An electron and a proton

attract each other.

Hot water will cool to room temperature faster in a

black pot

Which force binds atoms together to form molecules?

electrical

When water at 4°C is heated it expands. When water at 4°C is cooled, it

expands

Energy transfer by convection is primarily restricted to

fluids

If you pick up a snowball, energy flows

from your finger to the ice

To say that an object is electrically polarized is to say

its charges have been rearranged.

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

less than the resistance of either lamp.

A wire that carries an electric current

may be electrically charged

A good reflector of radiation is a

poor absorber of radiation.

Increased air pressure on the surface of hot water tends to

prevent boiling

A positive ion has more

protons than electrons

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

repel or attract

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

series

Magnetism is due to the motion of electrons as they

spin on their axes and move around the nucleus

When heat is added to boiling water, water temperature

stays the same

It is commonly thought that a can of beverage will cool faster in the coldest part of a refrigerator. Knowledge of Newton's law of cooling

supports this common knowledge

Heat energy travels from an object with a high

temperature to an object with a lower temperature.

Sparks from a very hot Independence Day sparkler won't harm you is because

the energy per molecule is high, but the total energy transferred is small.

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

Ice tends to form at the

top surface of bodies of water.

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

twice what it should be

The cooling effect inside a refrigerator is produced by

vaporizing the refrigeration liquid.

The electric power of a lamp that carries 2 A at 120 V is

240W

When 100 J of heat is added to a system that performs 60 J of work, the thermal energy change of the system is

40J

Four amps of current exist in the primary coil of a transformer. The voltage across the primary coil is 110 V. What is the power output of the secondary coil?

440 W

For ice to form on a pond, all the water in the pond must cool to

4°C

Increasing the temperature of 50 grams of water by 1°C requires

50 calories

A coulomb of charge that passes through a 6-V battery is given

6 joules

If you use 10 J of work to push a coulomb of charge into an electric field, its voltage with respect to its starting position is

10 V.

Which would burn the most?

100 g of steam at 100°C

Two charges separated by one meter exert a 1-N force on each other. If the charges are pushed to 0.25-m separation, the force on each charge will be

16 N

When mechanical work is done on a system, there can be an increase in its

Both thermal energy and temperature

Objects can absorb heat energy by

Convection, radiation, and conduction

Which statement is correct?

Current flows through a circuit.

We are able to completely convert all of a given amount of heat into mechanical energy.

False

Energy transfer is measured in units of

Joules and Calories

If a substance radiates more energy than it absorbs, its

Temperature and thermal energy decrease

An object will normally be a net radiator of energy when its thermal energy is

can't say, because thermal energy is not temperature

In an ac circuit, the electric field

changes magnitude and direction with time

Magnetic field lines about a current-carrying wire

circle the wire in closed loops.

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

cools

Ice is put in a cooler in order to cool the contents. To speed up the cooling process, the ice can be

crushed

An ampere is a unit of electrical

current

When air expands and no thermal energy is exchanged, the air temperature will

decrease

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

decreases

Every proton in the universe is surrounded by its own

gravitational and electric field

If a compass is moved from the northern hemisphere to the southern hemisphere, its magnetic needle will change direction

hardly at all

The reason the Sun's radiant energy is of shorter wavelengths than the earth's is because the Sun

has a higher temperature than the earth.

Newton's law of cooling applies to objects that are

heating and cooling

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

helium

As a system becomes more disordered, entropy

increases

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

very light molecules

An electric motor and electric generator are

very similar devices.

Evaporation is a cooling process and condensation is a

warming process.

Which will increase temperature fastest when heat is applied?

water

Which of the following expands most when the temperature is lowered? Equal volumes of

water at 4°C

To say that evaporation is a cooling process is to say that the

water left behind cools.

The number of electrons delivered daily to an average American home by an average power utility in the mid 1980s was

zero

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

10J

When a pair of 1 ohm resistors are connected in series, their combined resistance is

2 ohms, and when in parallel, 1/2 ohm

When a 10-V battery is connected to a resistor, 2 A of current flow in the resistor. What is the resistor's value?

5 ohms

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

an igloo

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

decreases

If glass expanded more than mercury, then the column of mercury in a mercury thermometer would rise when the temperature

decreases

The fundamental force underlying all chemical reactions is

electrical

An electroscope is charged positively as shown by foil leaves that stand apart. As a negative charge is brought close to the electroscope, the leaves

fall closer together

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

helium

The moderate temperatures of coastal areas is due to water's

high specific heat capacity.

Food in a pressure cooker is cooked faster because of the

higher temperature

Compared to the polar ice caps, a hot cup of coffee has

higher temperature, but less thermal energy.

In a mixture of hydrogen gas, oxygen gas, and nitrogen gas, the molecules with the greatest average speed are those of

hydrogen

If you run a refrigerator in a closed room with the refrigerator door open, the room temperature will

increase

Suppose you rapidly stir some raw eggs with an eggbeater. The temperature of the eggs will

increase

When air is compressed and no thermal energy is exchanged, the air temperature will

increase

When an iron ring is heated, the hole becomes

larger

As compared to the same mass of completely liquid water, slushy water tends to make it

less dense

When a light switch is turned on in a dc circuit, the average speed of electrons in the lamp is

less than 1 cm/s.

Sand which is hot during the day and cold at night is because it has

low specific heat capacity

A material that increases in temperature relatively quickly has a

low specific heat capacity.

To turn 50 g of boiling water to steam requires

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

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

negatively charged.

To say that electric charge is conserved means that no case has ever been found where

net charge has been created or destroyed

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

neutrons in the nucleus.

To melt 50 g of 0°C ice requires

no calories

The current in a 100-W bulb connected to a 120-V source is

none of these

An inventor discovers a harmless and tasteless salt, which, when added to water changes its boiling point. The market value for this salt will be best if the salt

raises the boiling point of water.

If you heat a sealed container of air on a burner. The air will have an increase in

thermal energy, pressure, and temperature

A circuit is powered with a battery. Current flows

through both the battery and the rest of the circuit.

We are warmed by condensation because water molecules in the air that strike our bodies

transfer some of their kinetic energies to us.