The first law of thermodynamics states that ΔU = q + w, where ΔU is the increase in internal energy, q is the heat supplied to the gas and w is the work done on the gas. A gas releases 800 J of heat to its surroundings and is compressed, with 500 J of work done on it. What is the change in internal energy of the gas?

Q: How do I try a free CIE Physics question?

Just tap any of the four options on this page — no signup, no card, nothing to install. You'll see the correct answer and a full mark-scheme-style explanation within a second. Each visit shows a fresh randomly-picked question from the live CIE IGCSE Physics bank, so you can keep refreshing to try different ones before deciding whether to create a free account for daily access.

Q: Is Kramizo really free for CIE Physics students?

Yes — completely free. Every student gets 45 questions a day on the free plan, across any board and any subject, with no card required and no trial countdown. Kramizo's optional Pro plan removes the daily cap and adds analytics, but the free plan is genuinely free forever. We make money from the small percentage of students who choose to upgrade — not from selling data or ads.

Q: Are the Physics questions aligned to the CIE IGCSE syllabus?

Every question is written against the published CIE IGCSE Physics syllabus and reviewed for accuracy before being added to the bank. We match the command words (state, describe, explain, evaluate), mark allocations, and difficulty tier you'll see on real CIE past papers. Explanations are written in the style of official examiner mark schemes so students learn exactly what marks are being awarded for.

Question

The first law of thermodynamics states that ΔU = q + w, where ΔU is the increase in internal energy, q is the heat supplied to the gas and w is the work done on the gas. A gas releases 800 J of heat to its surroundings and is compressed, with 500 J of work done on it. What is the change in internal energy of the gas?

Accepted Answer

A. –300 J — Heat is released by the gas so q = –800 J. Work is done on the gas so w = +500 J. Therefore ΔU = q + w = –800 + 500 = –300 J, meaning the internal energy decreases by 300 J.

Answer

A. –300 J

Answer

C. –1300 J

Answer

B. +300 J

Answer

D. +1300 J

One real Physics question.No signup. 30 seconds.

One real Physics question.
No signup. 30 seconds.