Q&A Hero

Q: When an object absorbs as much as it radiates A) it remains at about the same temperature. B) it is a net absorber. C) it is a net radiator. D) none of the above

Q: Objects that radiate relatively well A) absorb radiation relatively well. B) reflect radiation relatively well. C) both of these D) neither of these

Q: The lower the temperature of an object, the A) lower the frequency of radiation it emits. B) longer the wavelengths it radiates. C) both of these D) neither of these

Q: The pupil of your eye is a net A) absorber of radiant energy. B) emitter of radiant energy. C) reflector of radiant energy. D) none of the above

Q: Terrestrial radiation is A) emitted by Earth. B) emitted by the Sun. C) both of these D) neither of these

Q: The higher the temperature of an object, the A) longer the wavelengths it radiates. B) shorter the wavelengths it radiates. C) makes no difference in the wavelengths it radiates

Q: Sun's radiant energy is composed of shorter wavelengths than Earth's due to Sun's greater A) size. B) surface temperature. C) both of these D) neither of these

Q: The form of heat transfer that doesn't depend on a medium is A) conduction. B) convection. C) radiation. D) all of the above

Q: If you release a single molecule in an evacuated region it will initially A) fall just as a baseball would. B) move in any direction. C) convect upward. D) be buoyed upward. E) none of the above

Q: If no molecular collisions occurred in a sample of gas, temperature of the gas would A) increase. B) decrease. C) be unaffected.

Q: In a mixture of hydrogen gas, oxygen gas, and nitrogen gas, the molecules with the greatest average speed are those of A) hydrogen. B) oxygen. C) nitrogen. D) all the same

Q: At the same temperature, which has greater average speed in the air? A) very light molecules B) heavier molecules C) both have equal average speeds.

Q: A parcel of warmed air rises due to A) random molecular motion. B) radiation. C) buoyancy. D) increased energy of its molecules.

Q: Steam that issues from a pressure cooker A) is invisible. B) cools as it expands. C) both of these D) neither of these

Q: A region of expanding air tends to A) cool. B) warm. C) both of the these D) neither of these

Q: Molecules in a region of expanding air more often collide with neighboring molecules that are A) approaching. B) receding. C) nearly out of range.

Q: Blow on your hand with your mouth open. Then do the same with your lips puckered and you'll find A) a difference in temperatures. B) the breath from puckered lips is cooler. C) both of these D) neither of these

Q: When a volume of air is compressed, air temperature A) increases. B) decreases. C) neither of these

Q: If a volume of air is warmed, it expands and tends to A) warm. B) cool. C) neither of these

Q: You can safely hold your fingers on both sides of a candle flame due mainly to A) conduction. B) convection. C) radiation. D) none of the above

Q: Soaring birds and glider pilots can remain aloft for hours without expending power, due to A) conduction. B) convection. C) radiation. D) all of the above

Q: Energy transfer by convection is primarily restricted to A) solids. B) liquids. C) gases. D) fluids. E) none of the above

Q: The reason you can walk barefoot on red-hot coals of wood without burning your feet mainly involves A) low temperature of the coals. B) low conductivity of the coals. C) mind over matter techniques.

Q: In terms of transferring heat, red-hot wooden coals A) conduct quite well. B) conduct poorly. C) radiate poorly. D) convect poorly.

Q: If you were caught in freezing weather with only a candle for heat, you would be warmer in A) an igloo. B) a tent. C) a wooden house. D) a car.

Q: A water-filled paper cup held in a flame will not catch fire. This is because A) the inside of the paper is wet. B) water is an excellent conductor of heat. C) paper is a poor conductor of heat. D) the paper cup cannot become appreciably hotter than the water it contains.

Q: If air were a better conductor, at nighttime Earth would be A) considerably colder. B) considerably warmer. C) not appreciably different in temperature.

Q: A bare roof on a warmly heated home on a snowy day indicates A) an unwanted flow of heat B) poor insulation. C) fairly good conductivity. D) all of the above

Q: Wood is a poor conductor A) when it is cold. B) at common room temperature. C) when it is hot. D) all of the above E) none of the above

Q: When you touch a nail stuck in ice, energy flows from A) the ice to your hand. B) your hand to the ice. C) both of these D) neither of these

Q: In practice, a good insulator A) stops heat flow. B) slows heat flow. C) speeds negative heat flow. D) all of the above

Q: A block of wood and a block of copper will feel neither hot nor cold to the touch when they each have A) equal temperatures. B) your temperature. C) equal conductivities. D) none of the above

Q: On a cold day your feet feel warmer on a rug than on a tile floor because a rug A) is usually warmer than tile. B) is a poorer conductor. C) for the same mass has more internal energy than tile. D) all of the above E) none of the above

Q: Because of trapped air inside, snow is a A) good conductor. B) good insulator. C) both a good insulator and a poor conductor. D) none of the above

Q: Which of these are good insulators? A) feathers. B) wood. C) snow. D) all the above E) none of the above

Q: Which of these are good conductors? A) feathers. B) wood. C) snow. D) all the above E) none of the above

Q: A good heat conductor is A) a poor insulator. B) a good insulator. C) neither of these

Q: Metals are good conductors of both heat and electricity due to A) similar thermal and electrical conductive properties. B) looseness of outer electrons in metal atoms. C) relatively high densities of metals. D) high elasticity of metals. E) both transferring energy easily.

Q: When ice crystals collapse at the surface of ice, the result is a A) thin film of water. B) slippery surface. C) both of these. D) none of the above

Q: Ice crystals in nearly frozen liquid water make up a A) microscopic slush. B) region of lower density. C) both of these D) neither of these

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

Q: Ice has a lower density than water because ice A) molecules are more compact in the solid state. B) molecules vibrate at lower rates than water molecules. C) is composed of open-structured crystals. D) density decreases with decreasing temperature.

Q: Microscopic slush in ice water tends to make water density A) lower. B) higher. C) sustain at one value.

Q: Due to the presence of ice crystals in nearly frozen liquid water, the density of water is A) lower. B) unaffected. C) higher.

Q: Open spaces in ice crystals contribute to A) decreased density. B) increased density. C) neither of these

Q: When ice water at 0o C is heated A) thermal expansion occurs. B) thermal contraction occurs. C) both occur until 4oC is reached

Q: Which of these is correct? A) a piece of solid iron floats in molten iron. B) a piece of solid aluminum floats in molten aluminum. C) a piece of ice floats in water. D) all the above E) none of the above

Q: A body of water will be deeper when its A) temperature rises. B) temperature drops. C) neither of these

Q: If you measure the distance between two telephone poles with a steel tape on a very hot day, your measured distance will be A) a bit short. B) a bit long. C) the same as on an average-temperature day.

Q: If you measure the width of an outdoor barn with a steel tape on a very cold day, your measured width will be A) a bit short. B) a bit long. C) the same as on an average-temperature day.

Q: If glass expanded more than mercury, then the column of mercury in a mercury thermometer would fall when the temperature A) increases. B) decreases. C) neither of these

Q: Which of these expands when the temperature is lowered? A) iron B) wood C) ice water D) helium E) none of the above

Q: Which of the following contracts most when the temperature is decreased? Equal volumes of A) iron. B) wood. C) water. D) helium. E) all contract the same.

Q: Which of the following expands more when the temperature is increased? Equal volumes of A) iron. B) wood. C) ice water. D) helium. E) all expand the same.

Q: In most cases, which expands more for comparable changes in temperature? A) solids. B) liquids. C) gases. D) all expand about equally.

Q: The fact that gasoline overflows a full tank on a hot day is evidence that A) gasoline expands more with increasing temperature than its tank. B) the tank contracts while gasoline expands with temperature. C) both of these D) neither of these

Q: It is important that the two metals that compose a bimetallic strip have A) different conductivities. B) different rates of expansion. C) equal thicknesses. D) all of the above E) none of the above

Q: When a bimetallic bar made of copper and iron strips is heated, the bar bends toward the iron strip. The reason for this is A) iron gets hotter before copper. B) copper gets hotter before iron. C) copper expands more than iron. D) iron expands more than copper. E) none of the above

Q: Consider a metal ring with a gap cut in it. When the ring is heated, the gap A) becomes narrower. B) becomes wider. C) retains its size.

Q: As a piece of metal with a hole in it cools, the diameter of the hole A) increases. B) decreases. C) remains the same.

Q: 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.

Q: When we enlarge a photograph of an iron ring, the image of the hole becomes A) smaller. B) larger. C) neither smaller nor larger.

Q: When most substances are heated, molecules inside move faster and take up more space, resulting in thermal A) bending. B) expansion. C) contraction. D) heat.

Q: A closed, sealed can of air placed on a hot stove. The contained air undergoes an increase in A) mass. B) temperature. C) both of these D) neither of these

Q: In terms of thermal expansion it is important that A) a key and its lock are made of similar or the same material. B) the fillings in your teeth expand at the same rate as teeth. C) iron rods and concrete in which they're embedded expand equally. D) all of the above E) none of the above

Q: 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.

Q: If the specific heat capacity of water were lower than it is, a watermelon in a picnic cooler would cool in a A) shorter time. B) longer time. C) the same time anyway.

Q: If the specific heat capacity of water were lower than it is, a nice hot bath would be a A) shorter experience. B) longer experience. C) same regardless of water's specific heat capacity.

Q: The moderate temperatures of islands throughout the world has much to do with water's A) good conductivity. B) vast supply of internal energy. C) high specific heat capacity. D) high evaporation rate. E) absorption of solar energy.

Q: One of water's interesting thermal properties is that when heated it takes a relatively A) long time in changing temperature. B) short time in changing temperature. C) same amount of time to cool. D) none of the above

Q: The fact that desert sand is very hot in the day and very cold at night is evidence that the specific heat capacity of sand is relatively A) low. B) high. C) practically absent.

Q: Aluminum has a specific heat capacity more than twice that of copper. Place equal masses of aluminum and copper wire in a flame and the one to undergo the fastest increase in temperature will be A) copper. B) aluminum. C) both the same

Q: A substance that heats up relatively quickly has a A) high specific heat capacity. B) low specific heat capacity. C) either of these D) neither of these

Q: A substance that heats up relatively slowly has a A) high specific heat capacity. B) low specific heat capacity. C) either of these D) neither of these

Q: A substance that cools down faster than others has a A) low specific heat capacity. B) high specific heat capacity. C) either of these D) neither of these

Q: 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

Q: Tomatoes have a higher specific heat capacity than dough. This means that when you bite into a hot pizza A) the dough feels hotter than the tomato sauce. B) the tomato sauce feels hotter than the dough. C) since sauce and dough are at the same temperature, neither feels hotter.

Q: Aluminum has a higher specific heat capacity than iron. This means that for equal masses of aluminum and iron, the metal that heats more quickly when the same amount of heat is applied is A) aluminum. B) iron. C) need more information

Q: The specific heat capacity is highest for substances that absorb or release large quantities of heat for correspondingly A) small temperature changes. B) large temperature changes. C) small or large changes in temperature. D) none of the above

Q: Materials composed of molecules that absorb large amounts of energy in the form of internal vibrations and rotations have A) low specific heats. B) high specific heats. C) none of the above