THERMODYNAMICS SEMI-FINALS EXAMINATIONS

Which of the following statements best describes the first law of thermodynamics?

• Energy cannot be created or destroyed.

• Energy always flows from hot to cold.

• Entropy in a closed system always increases.

• Temperature is a measure of the average kinetic energy of particles.

A gas undergoes an isothermal process. What can you conclude about the internal energy of the gas during this process?

• It remains constant.

• It increases.

• It decreases.

• It fluctuates.

In a thermodynamic process, if the work done by the system is negative, what can you infer about the system?

• It is losing energy to its surroundings.

• It is gaining energy from its surroundings.

• It is an isolated system.

• It is in a state of equilibrium.

A system absorbs 300 J of heat and does 50 J of work on its surroundings. What is the change in internal energy of the system?

• 150 J

• 250 J

• -150 J

• -250 J

Consider a closed system where no heat is exchanged with the surroundings. What can you conclude about the internal energy of the system?

• It remains constant.

• It increases.

• It decreases.

• It fluctuates.

If a system undergoes an adiabatic process, what can you infer about the heat exchange with the surroundings?

• No heat is exchanged.

• Heat is exchanged at a constant temperature.

• Heat is exchanged at a variable temperature.

• Heat is exchanged at a constant pressure.

A gas expands against a constant external pressure. What type of thermodynamic process is this?

• Isothermal

• Adiabatic

• Isobaric

• Isochoric

If the internal energy of a system is constant, what can be said about the heat exchange and work done by the system?

• Heat exchange is positive, and work done is negative.

• Heat exchange is negative, and work done is positive.

• Heat exchange and work done are both positive.

• Heat exchange and work done are both negative.

According to the first law of thermodynamics, what is the relationship between the heat added to a system and the work done by the system?

• They are always equal.

• Work done is always greater than heat added.

• Heat added is always greater than work done.

• There is no specific relationship.

In a cyclic process, what can you conclude about the change in internal energy of the system?

• It is zero.

• It is positive.

• It is negative.

• It cannot be determined.