O-LevelPhysicsThermal Physics5054/12 · Oct/Nov 2020 · Q221 Mark

A mass of gas is trapped inside a cylinder by a moving piston. As the piston moves in, the volume of the gas decreases but the temperature stays the same. What happens to the gas pressure, and why?

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Adecreases, the molecules have less room to move in the cylinder

Bdecreases, the molecules move more slowly between collisions

Cincreases, the molecules collide more frequently with the piston

Dunchanged, the temperature of the gas is constant

✓ Correct answer

C: increases, the molecules collide more frequently with the piston

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Topic: Thermal Physics, O-Level Physics (syllabus 5054). Multiple choice, 1 mark.
Source: O-Level Physics, Oct/Nov 2020 Paper 1 Variant 2, question 22.

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