Q. Temperature remaining constant, the pressure of gas is decreased by 20%. The percentage change in volume
A) Increases by 20%
B) Decreases by 20%
C) Increases by 25%
D) decreases by 25%
Explanation
(c) According to Boyle’s law
$p_{1}V_{1} = p_{2}V_{2}$
As the pressure is decreased by 20%, so
$p_{2} = \frac{80}{100}p_{1}$
$p_{1}V_{1} = \frac{80}{100}p_{1}V_{2}$
$V_{1} = \frac{80}{100}V_{2}$
Percentage increase in volume
$= \ \frac{V_{2} - V_{1}}{V_{1}} \times 100$
$= \ \frac{100 - 80}{80} \times 100 = 25\%$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.