Thermodynamics Quiz

Ten Thermodynamics questions combine heat, energy-balance, and efficiency calculations with concepts about equilibrium and entropy. Every answer is explained.

Free, with no sign-up.

For High school students and adults reviewing the topic.

About 14 minutes. 10 questions.

How does it work?

Choose one answer or enter a number in the stated unit, then check it.
Round only the final answer in a calculation.

What will you get?

Review a score and an explanation for every answer.

Question 1During heating, a 0.30 kg sample has constant specific heat 1200 J/(kg·K). Its temperature rises by 15 K with no phase change. Find heat supplied in J, rounded to one decimal place.

Enter a number in J.

Answers within 0.05 J of the expected value are accepted.

Question 2A system absorbs 820 J as heat and performs 310 J of work. Use heat into the system and work done by it as positive: ΔU = Q − W. Find ΔU in J, rounded to one decimal place.

Enter a number in J.

Answers within 0.05 J of the expected value are accepted.

Question 3Between reservoirs at 800 K and 320 K, a reversible engine operates. Find its Carnot efficiency as a percentage, rounded to one decimal place.

Enter a number in %.

Answers within 0.05 % of the expected value are accepted.

Question 4To remove 1260 J from its cold compartment, a refrigerator uses 420 J of work. Find its coefficient of performance with no unit, rounded to two decimals.

Enter a number.

Answers within 0.005 of the expected value are accepted.

Question 5After reaching equilibrium with each of two objects, a thermometer gives identical readings. What does the zeroth law imply about the objects?

They contain equal total internal energyThey have matching temperatures regardless of their massesTheir masses and chemical compositions must matchTheir temperatures differ in proportion to their volumes

Question 6A report says a sealed object contains a quantity of heat. Which description is more precise?

Its internal energy is stored; heat names a boundary transferIts heat is a substance conserved separately from other energyIts pressure is identical to the energy crossing the boundaryIts temperature is the stored amount measured in joules

Question 7A crystal becomes more ordered while releasing energy to its colder surroundings. Which entropy account must be checked?

The number of visible defects as the complete energy balanceThe visual neatness of the crystal as the entropy totalThe combined change of the material and its surroundingsThe material’s decrease as a violation regardless of the surroundings

Question 8Ice melts at its melting point under fixed pressure while energy enters. Why can its temperature stay constant?

A constant reading proves that no energy crossed the boundaryThe solid’s mass doubles to keep each particle at the same temperatureEnergy rearranges the phase instead of raising the thermal stateThe incoming energy disappears from the conservation account

Question 9A cyclic engine proposal converts heat from a single reservoir completely into work. Which objection applies even if its energy totals balance?

The second law forbids that sole result of a cycleEnergy conservation requires work output to exceed heat inputA cycle ends with a permanent increase of the working fluid’s state energyThe first law prevents energy from ever crossing a boundary

Question 10Gas is enclosed in a piston that moves and can conduct energy through its walls. Which system classification fits?

Isolated, because the piston encloses the gasNeither open nor closed until its temperature reaches zeroOpen, because a moving boundary implies escaping matterClosed, with energy exchange but no matter crossing

Answer every question to see and share your score.

Read the topic guide