Understanding Heat Cycles in Science

What is the Carnot cycle primarily used to illustrate in thermodynamics?

• The efficiency of real-world engines

• The maximum possible efficiency of a heat engine

• The energy loss in a heat engine

• The speed of a heat engine

Which of the following is a key assumption of the Carnot cycle?

• The cycle operates with no heat exchange

• The cycle operates between two reservoirs at the same temperature

• The cycle is reversible and operates between two heat reservoirs

• The cycle is irreversible and operates between multiple heat reservoirs

In the Carnot cycle, what is the role of the isothermal expansion process?

• To increase the temperature of the working substance

• To absorb heat from the hot reservoir

• To reject heat to the cold reservoir

• To compress the working substance

Which of the following statements is true about real-world heat cycles compared to the Carnot cycle?

• Real-world cycles are more efficient than the Carnot cycle

• Real-world cycles are less efficient due to irreversibilities

• Real-world cycles operate without any heat loss

• Real-world cycles do not require a working substance

What is the primary reason that real-world heat engines cannot achieve Carnot efficiency?

• They operate at higher temperatures

• They have friction and other irreversibilities

• They use different working substances

• They operate in a vacuum

In a real-world heat engine, what is typically done to improve efficiency?

• Increase the temperature of the cold reservoir

• Decrease the temperature of the hot reservoir

• Minimise energy losses and improve insulation

• Use a larger working substance

In the context of heat cycles, what does the term "thermal efficiency" refer to?

• The amount of work done by the engine

• The ratio of work output to heat input

• The speed at which the engine operates

• The temperature difference between the reservoirs

Which of the following processes is not part of the Carnot cycle?

• Isothermal expansion

• Isothermal compression

• Adiabatic expansion

• Isobaric expansion