Conceptual Physics test 2

Which temperature scale has 373 as the boiling point of water? A) Fahrenheit B) Celsius C) Centigrade D) Kelvin

D) Kelvin

Which could 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) 100 g of steam at 100 degrees C

When cooking a potato in a conventional oven it is useful to stick a nail in it, which makes it cook faster. This is because A) the nail is a good radiator of heat B) the nail promotes convection in the potato C) the nail is a good conductor of heat D) the nail gets much hotter than anything in the oven

C) the nail is a good conductor of heat

If you double the absolute temperature of a star, its power output increases by a factor of A) 2 B) 4 C) 8 D) 16

D) 16

The air in this room has A) mass. B) weight. C) energy. D) all of these E) none of these

D) all of these

A shiny, white transparent surface prevents heat transfer because A) It has emissivity of zero and reflects all light that strikes it. B) It has emissivity of 1 and reflects all light that strikes it. C) It has emissivity of zero and absorbs all light that strikes it. D) It has emissivity of 1 and absorbs all light that strikes it.

A) It has emissivity of zero and reflects all light that strikes it.

Suppose you try to cool your home in the summer by letting heat flow from your house to your neighbor's home. You will A) Not get far, because of the zeroth law of thermodynamics B) Not get far, because of the first law of thermodynamics C) Have a cool house in a couple hours D) Have a warmer house in a couple hours

A) Not get far, because of the zeroth law of thermodynamics

"Two objects in thermal equilibrium with a third object are in thermal equilibrium with each other." Which Law of Thermodynamics is this? A) Zeroth B) First C) Second D) Third

A) Zeroth

The fact that desert sand is very hot in the day and very cold at night is evidence that sand has A) a low specific heat. B) a high specific heat. C) no specific heat.

A) a low specific heat.

In a vacuum, an object has no A) buoyant force. B) mass. C) weight. D) temperature. E) all of these

A) buoyant force.

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 A) faster. B) slower. C) in the same amount of time. D) None of the above choices are true.

A) faster.

When you touch a cold piece of ice with your finger, energy flows A) from your finger to the ice. B) from the ice to your finger. C) actually, both ways.

A) from your finger to the ice.

An iron block is placed in a furnace where it is heated and consequently expands. In the expanded condition, its density A) is less. B) is the same. C) is more.

A) is less.

Pumice is a volcanic rock that floats. Its density is A) less than the density of water. B) equal to the density of water. C) more than the density of water.

A) less than the density of water.

Compared to the volume of a kilogram of feathers, the volume of a kilogram of lead is A) less. B) more. C) the same.

A) less.

If the specific heat of water were lower than it is, ponds in the cold of winter would be A) more likely to freeze. B) less likely to freeze. C) neither more nor less likely to freeze.

A) more likely to freeze.

The buoyant force on an object is least when the object is A) partly submerged. B) submerged near the surface. C) submerged near the bottom. D) none of these

A) partly submerged.

When a gas is changed to a liquid state, the gas A) releases energy. B) absorbs energy. C) neither releases nor absorbs energy. D) both releases and absorbs energy.

A) releases energy.

Ice tends to form first at the A) surface of bodies of water. B) bottom of bodies of water. C) surface or bottom depending on the water depth.

A) surface of bodies of water.

The fact that a thermometer "takes its own temperature" illustrates A) thermal equilibrium. B) energy conservation. C) the difference between heat and internal energy. D) the fact that molecules are constantly moving.

A) thermal equilibrium.

A completely submerged object always displaces its own A) volume of fluid. B) weight of fluid. C) density of fluid. D) all of these E) none of these

A) volume of fluid.

When water vapor condenses on the inside of a window, the room becomes slightly A) warmer. B) cooler. C) neither warmer nor cooler.

A) warmer.

A balloon is buoyed up with a force equal to the A) weight of air it displaces. B) density of surrounding air. C) atmospheric pressure. D) weight of the balloon and contents. E) all of these

A) weight of air it displaces.

Suppose you walk on red-hot coals with bare feet. If bits of the coals do not stick to your feet, it would be best if your feet are A) wet. B) dry. C) warm. D) cold. E) very hot.

A) wet.

Before ice can form on a lake, all the water in the lake must be cooled to A) zero degrees C. B) 4 degrees C. C) minus 32 degrees C. D) None of the above. Ice can form at the surface regardless of the water temperature below.

B) 4 degrees C.

A 500N blimp hovers in the air. The buoyant force acting on it is A) zero. B) 500N . C) less than 500N. D) more than 500N. E) None of the above

B) 500N

Lead sinkers actually float on the surface of liquid mercury. Which takes up more space: 1 kg of mercury or 1 kg of lead? A) Mercury B) Lead C) Neither take up any space D) Not enough information is given

B) Lead

You fill two identical mugs with coffee, but the coffee in one mug is at a higher temperature than that in the other mug. You place the two mugs simultaneously in a microwave oven and turn it on briefly. As a result, you add 1 joule of thermal energy to each mug. Which mug experiences the larger increase in entropy (if any)? A) The two mugs experience equal increases in entropy. B) The mug containing the colder coffee experiences the larger increase in entropy. C) Neither mug experiences any increase in entropy. D) The mug containing the hotter coffee experiences the larger increase in entropy.

B) The mug containing the colder coffee experiences the larger increase in entropy.

Near the top of a mountain, water in an open pot boils at A) a higher temperature than at sea level. B) a lower temperature than at sea level. C) the same temperature as at sea level. D) None of the above choices are true.

B) a lower temperature than at sea level.

When a solid is changed to a liquid state, the solid A) releases energy. B) absorbs energy. C) neither releases nor absorbs energy. D) both releases and absorbs energy.

B) absorbs energy.

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 A) less than 30 degrees C. B) at or about 30 degrees C. C) more than 30 degrees C.

B) at or about 30 degrees C.

Water pressure is greatest against the A) top of a submerged object. B) bottom of a submerged object. C) sides of a submerged object. D) is the same against all surfaces E) none of these

B) bottom of a submerged object.

When an object is partly or wholly immersed in a liquid, it is buoyed up A) by a force equal to its own weight. B) by a force equal to the weight of liquid displaced. C) and floats because of Archimedes principle. D) but nevertheless sinks. E) none of these

B) by a force equal to the weight of liquid displaced.

The gulf stream is one of nature's ways of transferring energy through A) conduction. B) convection. C) transmission. D) radiation.

B) convection.

Wind is one of nature's ways of transferring energy through A) conduction. B) convection. C) transmission. D) radiation.

B) convection.

Melting snow A) warms the surrounding air. B) cools the surrounding air. C) neither warms nor cools the surrounding air. Ans: B

B) cools the surrounding air.

Consider a sample of ice at 0 degrees C. If the temperature is decreased, the volume of the ice A) increases. B) decreases. C) stays the same.

B) decreases.

Consider a sample of water at 0 degrees C. If the temperature is slightly increased, the volume of the water A) increases. B) decreases. C) remains the same.

B) decreases.

If the mass of an object were to double while its volume remains the same, its density would A) halve. B) double. C) stay the same. D) become four times as great.

B) double.

When gas in a container is squeezed to half its volume, its density A) halves. B) doubles. C) quadruples. D) remains the same.

B) doubles.

When water at 4 degrees C is heated slightly it expands. When water at 4 degrees C is cooled slightly, it A) contracts. B) expands. C) neither contracts nor expands.

B) expands.

For increased atmospheric pressure, the boiling temperature of a liquid A) goes down. B) goes up. C) remains at 100 degrees C.

B) goes up.

When a boat sails from fresh water to salt water, the boat will float A) lower in the water. B) higher in the water. C) at the same water level. D) None of the above

B) higher in the water.

It is a hot summer day and your friend's apartment has no air conditioning. However, a brand new refrigerator lies unopened in the center of the living room. Being a creative person, your friend closes all the doors and windows of the apartment, unpacks the refrigerator, plugs it in, and turns it on. Your friend then opens the refrigerator door and uses a small fan to circulate the air past the refrigerator and throughout the room. After the refrigerator has operated for a few minutes, the average temperature in the room is A) lower than it was before. B) higher than it was before. C) the same as it was before and the temperature is uniform throughout the room. D) the same as it was before, but some regions are hotter and others are colder.

B) higher than it was before.

Which of the following normally warms up fastest when heat is applied? A) water B) iron C) glass D) wood E) All of the above choices are equally true.

B) iron

When an iron ring is heated, the hole becomes A) smaller. B) larger. C) neither smaller nor larger. D) either smaller or larger, depending on the ring thickness.

B) larger.

A lobster crawls onto a bathroom scale submerged at the bottom of the ocean. Compared to its weight above the surface, the lobster will have an apparent weight under water that is A) greater. B) less. C) the same.

B) less.

In the poem "When You Are Old" by William Butler Yeats there is the following concluding line: "and bending down beside the glowing bars, murmur, a little sadly, how love fled and paced upon the mountains overhead and hid his face amid a crowd of stars." The glowing bars refer the metal bars that hold wood in a fireplace and they are transmitting heat energy by A) radiation only B) radiation and conduction. C) conduction only D) convection

B) radiation and conduction.

People fighting forest fires carry emergency tents that have shiny aluminum outer surfaces. If there is trouble, a fire fighter can lie under the tent to block the heat from burning trees overhead. The tent helps because A) conduction carries heat downward toward the fire fighter and the aluminum tent conducts that heat harmlessly into the ground. B) radiation carries heat downward toward the fire fighter and the aluminum tent reflects most of that radiation. C) convection carries heat downward toward the fire fighter and the aluminum tent blocks most of the heat carried by convection. D) both conduction and radiation carry heat downward toward the fire fighter and the aluminum tent blocks most of that heat.

B) radiation carries heat downward toward the fire fighter and the aluminum tent reflects most of that radiation.

When liquids change to a solid state, they A) absorb energy. B) release energy. C) neither absorb nor release energy. D) both absorb and release energy. Ans:B

B) release energy.

An egg is placed at the bottom of a bowl filled with water. Salt is slowly added to the water until the egg rises and floats. From this experiment, one concludes A) calcium in the egg shell is repelled by sodium chloride. B) the density of salt water exceeds the density of egg. C) buoyant force does not always act upward. D) salt sinks to the bottom.

B) the density of salt water exceeds the density of egg.

Housing and natural animal insulation works because A) the insulating materials are poorer heat conductors than air. B) the insulating materials trap air and prevent convection. C) the insulating materials prevent radiation D) the insulating materials reflect radiation

B) the insulating materials trap air and prevent convection.

Evaporation is a cooling process because A) heat is radiated during the process. B) the more energetic molecules are able to escape the liquid. C) the temperature of the remaining liquid increases. D) none of these

B) the more energetic molecules are able to escape the liquid.

When a chocolate bar is cut in half, its density is A) halved B) unchanged C) doubled D) None of the above

B) unchanged

A dam is thicker at the bottom than at the top partly because A) water is denser at deeper levels. B) water pressure is greater with increasing depth. C) surface tension exists only on the surface of liquids. D) it looks better. E) none of these

B) water pressure is greater with increasing depth.

Airplane flight best illustrates A) Archimedes' principle. B) Pascal's principle. C) Bernoulli's principle. D) None of the above

C) Bernoulli's principle.

Which has the greater density, a lake full of water or a cup full of lake water? A) the cup full of lake water B) the lake full of lake water C) Both have the same density D) It is impossible to tell without knowing the size of the lake.

C) Both have the same density

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) Choices A and B are both correct. D) Choices A and B are both incorrect.

C) Choices A and B are both correct.

Heat energy is measured in units of A) joules. B) calories. C) Choices A and B are both true. D) Kelvin

C) Choices A and B are both true.

Atmospheric molecules do not fly off into outer space because of A) their relatively high speeds. B) their relatively low densities. C) Earth gravitation. D) cohesive forces.

C) Earth gravitation.

Why are good thermal conductors generally good electric conductors also? A) Heat and electricity are the same things. B) The molecules in both don't move around very much. C) Electron motion is responsible for determining both properties. D) The answer depends on the specific metal.

C) Electron motion is responsible for determining both properties.

Which of the following quantities is not conserved? A) Energy B) Angular momentum C) Entropy D) Momentum

C) Entropy

Why does an ice cube feel cold? A) Heat from your hand enters the cube by convection. B) Cold from the cube enters your hand by convection. C) Heat from your hand enters the cube by conduction. D) Cold from the cube enters your hand by conduction.

C) Heat from your hand enters the cube by conduction

Which temperature scale has 273 as the boiling point of water? A) Fahrenheit B) Celsius C) No scale D) Kelvin

C) No scale

"The entropy of an isolated system never decreases." Which Law of Thermodynamics is this? A) Zeroth B) First C) Second D) Third

C) Second

An umbrella tends to move upwards on a windy day principally because A) air gets trapped under the umbrella, warms, and rises. B) buoyancy increases with increasing wind speed. C) air pressure is reduced over the curved top surface. D) all of these

C) air pressure is reduced over the curved top surface.

The pressure in a liquid depends on liquid A) density. B) depth. C) both of these D) neither A or B

C) both of these

The first law of thermodynamics is a re - statement of the law of A) conservation of momentum B) thermal equilibrium C) conservation of energy D) averages

C) conservation of energy

When heat is added to boiling water, its temperature A) increases. B) decreases. C) does not change.

C) does not change.

Two equal-sized buckets are filled to the top with water. One of the buckets has a piece of wood floating in it, making its total weight __________. A) more than the weight of the other bucket B) less than the weight of the other bucket C) equal to the weight of the other bucket D) None of the above

C) equal to the weight of the other bucket

When you float in fresh water, the buoyant force that acts on you is equal to your weight. When you float higher in the high-density water of the Dead Sea, the buoyant force that acts on you is A) greater than your weight. B) less than your weight. C) equal to your weight.

C) equal to your weight.

Freezing is a _______ ______ that requires energy ________ for the melting system. A) phase transition; input B) chemical change; input C) phase transition; release D) chemical change; release

C) phase transition; release

When an ice cube in a glass of water melts, the water level A) rises. B) falls. C) remains the same.

C) remains the same.

You are riding in a hot air balloon. You have not used the burner for some time and the balloon begins to sink. Assuming that no air is allowed to leave or enter the balloon, A) the average density of the balloon remained constant and the buoyant force on the balloon became less than its weight. B) the average density of the balloon became greater than the surrounding air and the buoyant force on the balloon remained constant. C) the average density of the balloon became greater than the surrounding air and the buoyant force on the balloon became less than its weight. D) the balloon became heavier.

C) the average density of the balloon became greater than the surrounding air and the buoyant force on the balloon became less than its weight.

A rock suspended by a string weighs 5 N out of water and 3 N when submerged. What is the magnitude of the buoyant force on the rock? A) 8N B) 5N C) 3N D) 2N E) none of these

D) 2N

You are watching a science fiction movie where people on a space ship are traveling around the universe observing stars with different temperatures. Which of the following stars has the lowest surface temperature? A) A bluish star B) A yellowish star C) The sun D) A reddish star

D) A reddish star

If a loaf of bread is compressed, its A) surface tension becomes less. B) molecules become harder. C) density decreases. D) density increases. E) none of these

D) density increases.

Food cooked in boiling water at a mountain top cooks slower than when cooked at sea level. If the temperature under the pot of boiling water is increased, the food will cook A) faster at the mountain top. B) faster at sea level. C) faster at both places. D) no differently than it did before the increase.

D) no differently than it did before the increase.

The reason that buoyant force acts upward on a submerged object is that A) it acts in a direction to oppose gravity. B) if it acted downward, nothing would float. C) the weight of fluid displaced reacts with an upward force. D) upward pressure against the bottom is greater than downward pressure against the top of the submerged object.

D) upward pressure against the bottom is greater than downward pressure against the top of the submerged object.

Ice is put in a cooler to cool the contents. To speed up the cooling process, the ice can be A) wrapped in newspaper. B) drained of ice water periodically. C) kept out of contact with the food. D) kept in one solid chunk. E) covered with salt.

E) covered with salt.

Ice cubes submerged at the bottom of a liquid indicate that the liquid A) produces no buoyant force on the ice. B) has dissolved air. C) is warmer than the ice. D) is not displaced by the submerged ice. E) is less dense than ice.

E) is less dense than ice.

The reason a life jacket helps you float is A) the jacket makes you weigh less. B) the jacket has the same density as an average human. C) the jacket repels water. D) if you sink, the jacket sinks. E) the density of both you and the jacket together is less than your density alone.

E) the density of both you and the jacket together is less than your density alone.

Consider water that freezes into ice when put in your freezer, so the water goes from being disordered to being relatively ordered. Please explain if the freezing of the ice violated the second law of thermodynamics.

No the second law is not violated; the entropy of the universe still increased. Although locally the ice froze and its entropy went down, there is a greater entropy increase due to the heat being dissipated outward from the freezer coils. So when you add it all up, the entropy of the universe increased.