Question

Given $P_{atm}=76\text{cm of Hg}$.
The length of the air column in fig, when the open end is placed vertically down is:

• A. 10.85 cm
• B. 11.41 cm
• C. 12.85 cm
• D. 13.41 cm

Answer 1

The correct option is D 13.41 cm

Concept involved is Boyle's law.
$(12\text{cm}\times A)\times 76\text{cm}=(l\times A)\times 68$
$l=12\times \frac{76}{68}=13.41\text{cm}$