QJEEM14Ph21fc: JEE Main 2014 Physics - Class 11 JEEM14Ph21fc Solution: An open glass tube is immersed in mercury in such a way that a…

Question

Verified Solution • 2025–26 Session moderate

An open glass tube is immersed in mercury in such a way that a length of

8

c m

extends above the mercury level. The open end of the tube is then closed and scaled and the tube is raised vertically up by additional

46

c m

. What will be length of the air column above mercury in the tube now? (Atmospheric pressure

= 76

c m

of

H g

)

Accepted Answer

Length of the air column above mercury in the tube is,

P + x = P_{0}

\Rightarrow P = (76 - x)

\Rightarrow 8 \times A \times 76 = (76 - x) \times A \times (54 - x)

∴

x = 38

Thus, length of air column

= 54 - 38 = 16 c m .

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