If speed of gas molecules increases by twice on heating. What will be their kinetic energy?
Correct answer: B. increases by four times
- A. increases by two times
- B. increases by four times
- C. decreases by two times
- D. decrease by four times
Explanation
The average translational kinetic energy of gas molecules is proportional to the square of their speed, KE = 1/2 mv^2. If speed doubles, KE becomes 1/2 m(2v)^2 = 4 x 1/2 mv^2, so it increases four times. Students who choose two times are applying direct proportionality to speed instead of square proportionality.
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About Kinetic Molecular Theory
Kinetic molecular theory explains gases as rapidly moving particles separated by large distances, with negligible volume and negligible intermolecular attraction in the ideal model. It relates temperature to average kinetic energy and explains gas pressure, Boyle's and Charles's laws, diffusion, effusion and the conditions under which real gases deviate from ideal behavior.
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