In the J-tube above, Y and X are on the same horizontal level and 30cm3 of air is trapped above Y when the atmospheric pressure is 75cm Hg, calculate the volume of air trapped above Y when 15cm Hg is now poured into the limb above X
Attached Figure / Diagram
A
15 cm3
B
25 cm3
C
35 cm3
D
45 cm3
Verified Correct Answer: B.
Physical Principles & Numerical Solution
Since the temperature of the air is to remain constant, => P\(_1\)V\(_1\) = P\(_2\)V\(_2\)
∴ 75 x 30 = (75 + 15) x V\(_2\)
75 x 30 = 90 x V\(_2\)
V\(_2\) = \(\frac{75 \times 30}{90}\)
\(\frac{2250}{90}\) = 25cm\(^2\)
Source: Myschool Past Questions Archive (Record #11174)