Questions from Modern Physics

Q: In an adiabatic process for an ideal gas, the pressure decreases

In an adiabatic process for an ideal gas, the pressure decreases. In this process does the internal energy of the gas increase or decrease? Explain.

Q: The efficiency of heat engines is high when the temperature difference between

The efficiency of heat engines is high when the temperature difference between the hot and cold reservoirs is large. Refrigerators, on the other hand, work better when the temperature difference is sm...

Q: Household refrigerators have arrays or coils of tubing on the outside,

Household refrigerators have arrays or coils of tubing on the outside, usually at the back or bottom. When the refrigerator is running, the tubing becomes quite hot. Where does the heat come from?

Q: An ideal gas expands while the pressure is kept constant. During

An ideal gas expands while the pressure is kept constant. During this process, does heat flow into the gas or out of the gas? Justify your answer.

Q: Real heat engines, like the gasoline engine in a car,

Real heat engines, like the gasoline engine in a car, always have some friction between their moving parts, although lubricants keep the friction to a minimum. Would a heat engine with completely fric...

Q: When you use a hand pump to inflate the tires of your

When you use a hand pump to inflate the tires of your bicycle, the pump gets warm after a while. Why? What happens to the temperature of the air in the pump as you compress it? Why does this happen? W...

Q: In the carburetor of an aircraft or automobile engine, air flows

In the carburetor of an aircraft or automobile engine, air flows through a relatively small aperture and then expands. In cool, foggy weather, ice sometimes forms in this aperture even though the outs...

Q: What would be the efficiency of a Carnot engine operating with TH

What would be the efficiency of a Carnot engine operating with TH = TC ? What would be the efficiency if TC = 0 K and TH were any temperature above 0 K? Interpret your answers.

Q: The prevailing winds on the Hawaiian island of Kauai blow from the

The prevailing winds on the Hawaiian island of Kauai blow from the northeast. The winds cool as they go up the slope of Mt. Waialeale (elevation 1523 m), causing water vapor to condense and rain to fa...

Q: Applying the same considerations as in Question Q19.17, explain

Applying the same considerations as in Question Q19.17, explain why the island of Niihau, a few kilometers to the southwest of Kauai, is almost a desert and farms there need to be irrigated. Question...