Which one of these cites the lowest temperature? |
270K |
What are the temperatures for freezing water and boiling water on the Kelvin temperature scale? |
273 k, 373 k |
When we speak about heat we refer to ___________. |
energy in transit |
In which direction does heat flow spontaneously between hot and cold objects? |
From high temperature to low temperature |
How is heat similar to and different from internal energy? |
They are both forms of energy, but heat flows, whereas internal energy does not. |
Does a hot object contain internal energy or does it contain heat? |
Internal energy |
The air in your room is composed of molecules that have |
a wide variety of speeds. |
Temperature is most closely related to molecular |
kinetic energy. |
Which temperature scales have equal sized degrees? |
Celsius and Kelvin |
When you touch a cold piece of ice with your finger, energy flows |
from your finger to the ice. |
Heat energy travels from an object with a high |
temperature to an object with a lower temperature. |
Distinguish between a calorie and a Calorie. |
A Calorie is 1000 calories. |
Hot sand cools off faster at night than plants and vegetation. This indicates that the specific heat capacity for sand is ___________. |
less than that of plants |
Does a substance that heats up quickly have a high or a low specific heat capacity? |
A low specific heat capacity |
Water is most dense at ___________. |
4°C |
How does the specific heat capacity of water compare with the specific heat capacities of other common materials? |
Water has a higher specific heat capacity than most common materials |
Why is the temperature fairly constant for landmasses surrounded by large bodies of water? |
Water has a high specific heat capacity. |
Why do substances expand when their temperature is increased? |
Higher-temperature substances have greater molecular motion. |
Why is ice less dense than water? |
Ice crystallizes with an open structure, and the gaps that form between the water molecules in ice increase its volume. |
Does "microscopic slush" in water tend to make it more dense or less dense? |
less dense |
Why does all the water in a lake have to be cooled to 4°C before the surface water can be cooled below 4°C? |
When water is cooled to 4°C, it sinks and deeper, warmer, water rises to the surface. |
Which temperature scale has the smallest sized degrees? |
Fahrenheit |
A temperature difference of 10 Celsius degrees is also equal to a temperature difference of 10 on the |
Kelvin scale. |
Room temperature on the Kelvin scale is about |
300K |
When you touch a hot potato with your finger, energy flows |
from the potato to your finger. |
Heat energy is measured in units of |
both of these (calories, joules) |
The amount of heat needed to raise the temperature of 1 gram of water by 1°C is |
4.19 joules. |
When 10 grams of hot water cool by 1°C, the amount of heat given off is |
41.9 joules. |
Pour a liter of water at 40°C into a liter of water at 20°C and the final temperature of the two becomes |
at or about 30°C. |
Pour two liters of water at 40°C into one liter of water at 20°C and the final temperature of the two becomes |
more than 30°C. |
Place a 1-kilogram block of iron at 40°C into 1 kilogram of water at 20°C and the final temperature of the two becomes |
less than 30°C |
A substance with a high thermal inertia has a high |
specific heat capacity. |
Materials composed of molecules that absorb large amounts of energy in the form of internal vibrations and rotations have |
high specific heats. |
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 |
Iron |
A substance that cools down faster than others has a |
low specific heat capacity. |
A substance that heats up relatively slowly has a |
high specific heat capacity |
If the specific heat capacity of water were lower than it is, a nice hot bath would be a |
shorter experience. |
When most substances are heated, molecules inside move faster and take up more space, resulting in thermal |
expansion. |
When an iron ring is heated, the hole becomes |
larger |
Consider a metal ring with a gap cut in it. When the ring is heated, the gap |
becomes wider |
Due to the presence of ice crystals in nearly frozen liquid water, the density of water is |
lower |
If you wish to expand the volume of a sample of water at 4°C |
either of these |
When water at 4°C is heated it expands. If it is instead cooled it will |
also expand |
Before ice can form on a lake, all the water in the lake must be cooled to |
4°C. |
What is the role of "loose" electrons in heat conductors? |
Free electrons can move through a material carrying heat, jostling atoms and other electrons. |
If you touch the metal sides in an oven with your bare hand, you’re in trouble. But hold your hand briefly in the oven air and you’re okay. What does this tell you about the relative conductivities of metal and air? |
Metal is a good conductor of heat, whereas air is a terrible conductor of heat. |
Explain why a firewalker can step quickly without harm on red-hot coals with bare feet. |
Wood, even as glowing coals, is a poor conductor of heat. |
Why are materials such as wood, fur, feathers, and even snow good insulators? |
Outer electrons in these materials are firmly attached. |
Does a good insulator prevent heat from escaping or slow its passage? |
Insulators slow the passage of heat |
When an air molecule is hit by an approaching, faster moving molecule, does the approaching molecule’s rebound speed increase or decrease? How about when it hits a receding molecule? |
Increase, decrease |
How are the speeds of molecules of air affected when the air is compressed by the action of a tire pump? What happens to the temperature of the air? |
Speeds increase; temperature increases. |
Why does the direction of coastal winds change from day to night? |
The specific heat of water is greater than the specific heat of land. Water cools more slowly at night. The temperature difference drives convection and offshore winds. |
Heat travels from the Sun to Earth by the process of _________. |
radiation |
In what form does radiant energy travel? |
As electromagnetic waves |
Relatively speaking, do high-frequency waves have long wavelengths or short wavelengths? Name an electromagnetic wave with higher frequency than blue light. |
Short, ultraviolet |
How does the peak frequency of radiant energy relate to the absolute temperature of the radiating source? |
The peak frequency increases as temperature increases. |
What is terrestrial radiation? |
Terrestrial radiation is infrared radiation emitted by Earth’s surface. |
Since all objects emit energy to their surroundings, why don’t the temperatures of all objects continuously decrease? |
Objects that are good emitters are equally good absorbers, so they absorb radiation as well as emit it. |
What determines whether an object is a net absorber or a net emitter of radiant energy at a given time? |
It is determined by the temperature of the object relative to its surroundings. Hotter objects are net emitters. |
Which will normally warm faster: a black pot of cold water or a silvered pot of cold water? Which will cool faster? |
black,black |
Can an object be both a good absorber and a good reflector at the same time? |
No. A good absorber reflects very little light. |
What type of gas absorbs and re-emits infrared radiation? |
greenhouse gases |
How would increasing the density of air in the atmosphere affect the amount of infrared radiation returned by the atmosphere back toward Earth? |
The amount of infrared radiation would increase. |
How would decreasing the percentage of greenhouse gases affect the amount of infrared radiation reflected by the atmosphere back toward Earth? |
The amount of infrared radiation would decrease. |
Newton’s law of cooling applies to objects that undergo _________. |
cooling or warming |
Which will undergo the greater rate of cooling: a red-hot poker in a warm oven or a red-hot poker in a cold room (or do both cool at the same rate)? |
The poker in the cold room cools fastest |
Metals are good conductors of both heat and electricity due to |
looseness of outer electrons in metal atoms. |
A good heat conductor is |
a poor insulator. |
Which of these are good conductors? |
none of the above (feathers,snow,wood) |
On a cold day your feet feel warmer on a rug than on a tile floor because a rug |
is a poorer conductor. |
A block of wood and a block of copper will feel neither hot nor cold to the touch when they each have |
your temperature |
In practice, a good insulator |
slows heat slow |
If air were a better conductor, at nighttime Earth would be |
considerably colder. |
If you were caught in freezing weather with only a candle for heat, you would be warmer in |
an igloo. |
The reason you can walk barefoot on red-hot coals of wood without burning your feet mainly involves |
Low conductivity of the coals. |
The form of heat transfer that doesn’t depend on a medium is |
radiation. |
Sun’s radiant energy is composed of shorter wavelengths than Earth’s due to Sun’s greater |
Surface temperature |
The higher the temperature of an object, the |
shorter the wavelengths it radiates. |
If a pizza radiates more energy than it absorbs, its temperature |
decreases |
An apple pie will be a net emitter of energy when its temperature is |
higher than its surroundings. |
Which body glows with electromagnetic waves? |
all of the above (the sun, the earth, you and your classmates) |
Waves emitted by the Sun and terrestrial wave emissions are |
the same except for their frequencies and wavelengths. |
Long ago a runaway greenhouse effect transformed the planet |
venus |
When coal dust is spread on snow on a sunny day |
more melting occurs. |
Heat normally flows from objects of high |
temperature to objects of low temperature. |
A Thermos bottle has double glass walls with silver coating on the glass surfaces that face each other. The silver coating reduces energy transfer by |
radiation. |
When a hot object makes thermal contact with a cold object, the direction of |
internal energy flow is from hot to cold |
Physics Chapter 15
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