Exam 5: Temperature and Heat

What is the maximum efficiency of a heat engine operating between 293 Kelvins and 273 Kelvins, the temperatures at the surface and several hundred meters below the surface, respectively, of the ocean?

Heat transfer by radiation occurs via

Air at a temperature of 32° F has a relative humidity of 60%. If the temperature of the same air rises to 40° F, the relative humidity

In a gas of different types of molecules all at the same temperature, the speeds of the heavier molecules will generally be _____________ the speeds of the lighter molecules.

Heating the air in a hot air balloon reduces the air's _________.

A bimetallic strip is usable as a thermometer because of

You feel warm from the Sun at the beach because of heat radiation.

The Eiffel tower in Paris is made primarily of iron, whose coefficient of linear expansion is about 10 × 10 ^{− 6}/°C. On a cold day when the temperature is -10°C the Eiffel tower is 300 meters tall. Its height on a hot day when the temperature is 40°C is __________.

Heat flows from

When you add heat to ice, its temperature always stays constant.

Internal energy in a system can be changed by

In a steam engine, steam at 140°C in a turbine does work on an external system, and the steam leaves the turbine at 100°C. The efficiency of the steam engine is 5%. The relevant physical principle is the first law of thermodynamics.

At temperatures below their boiling point, liquids gradually go into the gas phase through a process called

specific heat capacity of ice = 2,000 J/kg-°C      latent heat of fusion of water = 334,000 J/kg      specific heat capacity of water = 4,000 J/kg-°C After the 1 kg block of ice melts, the amount of heat required to raise its temperature to 10°C is 3,340,000 J.

At 96° F the saturation density of air is 0.04 kg/m ³. If the weather report says the relative humidity is 90 % when the temperature is 96°F, the humidity is

The latent heat of vaporization of water is roughly 10 times the latent heat of fusion of water. The amount of heat required to boil away 1 kg of water is 10 times the amount of heat required to melt 1 kg of ice.

A hot pizza contains heat.

Solar energy

Natural processes tend to increase the entropy of thermodynamic systems.

A piston compresses a gas, while at the same time heat is lost to the surroundings. The temperature of the gas rises. This is governed by the __________ law of thermodynamics.