FAA Aviation Mechanic General (AMG)Physics, Math and Fluid LinesMedium
A confined gas at constant pressure occupies 15 cubic inches at an absolute temperature of 500°R. If the temperature is increased to 1,000°R while pressure remains constant, what is the new volume according to Charles's Law?
- A7.5 cubic inches
- B30 cubic inches
- C15 cubic inches
- D60 cubic inches
Show answer & explanationAnswer & explanation
Correct answer: B. 30 cubic inches
Charles's Law states V1/T1 = V2/T2 at constant pressure. Solving: V2 = V1 × (T2/T1) = 15 × (1,000/500) = 15 × 2 = 30 cubic inches.
Why the other options are wrong
- A. Results from dividing instead of multiplying by the temperature ratio.
- C. Assumes no change occurred, ignoring the temperature increase.
- D. Results from quadrupling instead of doubling the volume.
Charles's Law
At constant pressure, the volume of a gas is directly proportional to its absolute temperature.
- V1/T1 = V2/T2 (constant pressure)
- Temperature must be in absolute units (°R or K)
- Volume increases as temperature increases
- Used with Boyle's Law to form the Combined Gas Law
Memory trick: Charles heats the balloon and it grows — volume follows temperature.