Physics Exam 3 SLU Nikolo (Conceptual Questions)

Note the following properties: 1) number of molecule 2) temperature 3) latent heat 4) moment of inertia 5) pressure 6) volume Which four of the listed properties are needed to describe an ideal gas?

1, 2, 5, 6

To turn 50 g of boiling water to steam requires

27,000 calories

To melt 50 g of 0 degrees C ice requires

4000 calories

What is the theoretical efficiency of a Carnot engine that operates between 600 K and 300 K?

50%

The number of grams of ice that can be melted by 1 g of 100 degrees C steam is

8 grams

If you triple the absolute temperature of an object, it will radiate energy...

81 times faster

If a poor absorber of radiation were a good emitter, its temperature would be

A. Less than its surroundings

Which one of the following properties of a gas is NOT consistent with ideal gas? (#91 chapter 7)

A. The average speed of the gas molecules is smaller at high temperatures

Which involves the larger number of calories?

A. The condensation of 1 g of steam at 100 degrees C to 100 degrees C water

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

An igloo

Which would burn the most? A. 100 g of water at 100 degrees C B. 100 g of steam at 100 degrees C C. Both would be equally damaging

B.

In the mountains, water boils at

B. a lower temperature than at sea level

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

B. absorbs energy

A toy submarine made out of steel floats in a bathtub. The sub weighs one newton. If you completely submerged it, it would displace two newtons of water. What could you do to cause the sub to sink to the bottom of the tub?

B. add one newton of sand to the sub's interior, plus a little more

Oxygen molecules are 16 times more massive than hydrogen molecules. At a given temperature, how do their average molecular speeds compare? The oxygen molecules are moving

B. at ¼ the speed

According to Boyle's law, when the pressure of a gas increase at a constant temperature, its volume...

B. decreases

The second law of thermodynamics lead us to conclude that

B. disorder in the universe is increasing with the passage of time

Metals are both good heat conductors and also good electrical conductors because of the

B. looseness of outer electrons in metal atoms

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

B. raises the boiling point of water

When an inflated balloon is exposed to cold air...

B. the volume of the balloon decreases

The figure below shows a U-tube filled with liquid and the respective pressures P1 and P2 at each end. Which of the following statements is correct? (#83 chapter 7 if you want to look at the diagram in the book)

C. P2 is bigger than P1

Steam burns are more damaging than burns caused by boiling water because steam A. Gives up additional energy when it condenses B. Has more energy per kilogram than boiling water C. Both of these D. Neither of these

C. both of these

Warm air rises because faster moving molecules tend to move to regions of less A. Density B. Pressure C. Both of these

C. both of these

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

C. can't say, because thermal energy is not temperature

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

C. condensation of steam inside

When you are scuba diving, the pressure on your mask..

C. depends only on your depth, and not on how you are oriented

When a vapor condenses

C. heat energy leaves the substance

Oxygen molecules are 16 times more massive than hydrogen molecules. At a given temperature, the average molecular kinetic energy of oxygen, compared to hydrogen

C. is the same

Place a block of aluminum in a bucket of water filled to the brim. Water overflows. Place another block of equal mass, this time made out of lead, into an identical bucket of water filled to the brim. The lead block displaces_________.

C. less water

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 A. Faster B. Slower C. Neither of these

C. neither of these

A good reflector of radiation is a

C. poor absorber of radiation

A refrigerator

C. removes thermal energy from inside the refrigerator

A chunk of ice (T= -20 degrees C) is added to a thermally insulated container of cold water (T= 0 degrees C). What happens in the container?

C. some of the water freezes and the chunk of ice gets larger

If molecules in a sample gas moved so they completely missed each other, the gas's temperature would

C. stay the same

Complete the following statement: the absolute temperature of an ideal gas is directly proportional to...

C. the average translational kinetic energy of the gas

Evaporation is a cooling process because

C. the more energetic molecules are able to escape the liquid

Two containers of different shapes are filled with water to the same depth as shown in the figure. The pressure on the bottom surface is________. (#82 chapter 7 if you want to look at the diagram in the book)

C. the pressure on the bottom surface are equal

The cooling effect inside a refrigerator is produced by

C. vaporizing the refrigeration liquid

Which is true about the buoyant force? A. It is a consequence of increasing pressure at increasing depths B. It is equal to the weight of the object C. It is equal to the weight of the liquid displaced D. A and C are correct E. A, B, and C are correct

D.

Two identical aquariums are both filled with a liquid. Aquarium A contains water, and aquarium B contains a liquid that is denser than water. Which of the following statements is FALSE? A. pressure at the bottom of aquarium B > bottom of aquarium A. B. Pressure within each fluid is exerted equally in all directions. C. Mass of fluid in aquarium B > mass of fluid in aquarium A. D. Pressure at bottom of both aquariums is the same. E. Volume of fluid in aquarium B = volume of fluid in aquarium A.

D. Pressure at bottom of both aquariums is the same.

A substance can absorb heat energy by the process of... A. Conduction B. Convection C. Radiation D. All of the above E. evaporation

D. all of the above

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

D. crushed

Which of the following best explains why a hot air balloon rises?

D. hot air has a lower density than cold air

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

D. kinetic energy, but more speed

When the temperature of a gas decreases at constant volume, its...

D. pressure decreases

Bernoulli's equation states that the sum of the pressure and energy per unit volume along a horizontal pipe does which of the following, as measurements are taken along the pipe in the direction of fluid flow?

D. remains constant as the pipe diameter increases

Which one of the following factors is directly responsible for the pressure exerted by a confined gas?

D. the collision of gas molecules with the side of the containing vessel

A water-filled paper cup held in a flame will not catch fire. This is because

D. the paper cup cannot become appreciably hotter than the water it contains

According to Charles's law, when the temperature of a gas increases at a constant pressure, its...

D. volume increases

Bernoulli's principle says...

D. whenever the speed of a fluid increase, its internal pressure decreases

Which is true about Pascal's principle? A. Pressure is transmitted through a fluid in a diminished form B. Pressure is transmitted through a fluid in an undiminished form C. Pressure cannot be transmitted through a fluid D. Hydraulic lifts are an application of Pascal's principle E. B and D are correct

E. B and D are correct.

In a static liquid, the hydrostatic pressure at a given depth is a function of which of the following? A. Depth B. Surface air C. Liquid density D. Choices a and b are both valid E. Choices a, b, and c are all valid

E. Choices A, B, C.

Saturation occurs in air when the

E. air contains as many water molecules as it can contain at a given temperature

Which one of the following statements best explains why gases are not commercially sold by volume?

E. gas volume depends on temperature and pressure

A sample of an ideal gas is heated and its Kelvin temperature doubled. What happens to the average speed of the molecules in the sample?

E. increase by 1.4

In order to triple the average speed of the molecules in a given sample of gas, the temperature (measured in Kelvins) must

E. increase by a factor of 9

The temperature of an ideal gas increases from 3 degrees C to 6 degrees C while remaining at constant pressure. What happens to the volume of the gas?

E. it increase slightly

Compared to a glass of ice water with ice in it, a glass of plain ice-cold water without ice on a warm day will warm up

Faster

A good absorber of radiation is a

Good emitter of radiation

Food in a pressure cooker is cooked faster because of the

Higher temperature

Increasing the temperature of an ideal gas from 50 degrees C to 75 degrees C at constant volume will cause which of the following to increase for the gas? I. The average distance between the molecule II. The average speed of the molecules III. The average molecular mass of the gas

II. only

A sample of argon gas is sealed in a container. The volume of the container is doubled. If the pressure remains constant, what happens to the absolute temperature?

It's doubled.

When bringing water to a boil in the mountains, the time needed to reach the boiling point is

Less than at sea level

When the temperature of a gas at a constant volume increases, its...

Pressure increases

Increased air pressure on the surface of hot water tends to

Prevent boiling

If the pressure acting on an ideal gas at constant temperature is doubled, its volume is

Reduced to one-half

The surface of water can act like a sort of skin due to a property of liquids called...

Surface Tension

Which one of the following properties of a gas is not consistent with kinetic theory?

The average speed of the gas molecules is smaller at high temperatures

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

Transfer some of their kinetic energies to us

Is it possible to transfer heat from a cold reservoir to a hot reservoir?

Yes, but work will have to be done.

Objects that radiate relatively well...

absorb radiation relatively well.

Cold water will warm to room temperature faster in a

black pot

Hot water will cool to room temperature faster in a

black pot

If you want to cook eggs by boiling them while in the mountains, then compared to sea level cooking, you should...

boil the eggs for a longer period of time

By what primary heat transfer mechanism does one end of a metal spoon become hot when the other end is placed in boiling water?

conduction

The space between the inner walls of a thermos bottle is evacuated to minimize heat transfer by

conduction and convection

If air were a better conductor than it is, at nighttime the earth would be...

considerably colder

If your hands are being warmed by holding them above a flame, then the primary form of heat transfer is which process?

convection

When volume of air is compressed, it's temperature will...

decrease

When water freezes, the entropy of the water

decreases

What happens to water when heated from 0 degrees C to 4 degrees C?

density increases

What happens to water when its temperature is reduced from 12 degrees C to 4 degrees C?

density increases

If volume of air is warmed, it will

expand

What happens to a given mass of water when cooled between 4 and 0 degrees C?

expands

Energy transfer by convection is primarily restricted to

fluids

Your feet feel warmer on a rug than on a tile floor because the rug...

is a better insulator than the tiles

Double the absolute temperature of helium gas, and the molecules of helium, on average, speed up by

less than twice

Convection can occur

only in liquids and gases

A good heat conductor is a...

poor insulator

By what primary heat transfer mechanism does the sun warm the earth?

radiation

If holding hands to one side of a flame, the predominant form of heat transfer is what process?

radiation

The planet Earth loses heat mainly by

radiation

The silver coating on the glass surfaces of a Thermos bottle reduces energy that is transferred

radiation

When liquids change to a solid phase, they

release energy

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

releases energy

Suppose you are served hot coffee at a restaurant before you are ready to drink it. In order for it to be the hottest when you are ready for it, you should add cream...

right away

The primary reason why a sandy beach gets so hot on a sunny day is because

sand has a small specific heat., so it doesn't take much energy to heat it up 1 degree meaning it can heat up quickly.

Sea breezes on a beach are attributed to a difference between land and water with respect to what property?

specific heat

When heat is added to boiling water, the water temperature

stays the same

Suppose you walk on red hot coals with bare feet. Providing bits of coal do not stick to your feet, it would be best if your feet are...

wet