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A simple barometer is constructed using a liquid \(Q_{1}\...

A simple barometer is constructed using a liquid Q1 of density 16.2g/cm3. Calculate the least lenth of the tube to be used to measure pressure of 1.5atm.  [Density of mercury = 13.6g/cm3, 1atm = 76.0 cm of Mercury]

A.

1358mm

B.

957mm

C.

760mm

D.

638mm

Correct answer is D

Let hQ and ρQ be the least length and the density of Q1 

while h and ρ are the length and density of mercury respectively.

h×ρ×g=hQ×ρQ×g

76cm×13.6×10=hQ×16.2×10

hQ=76×13.6×1016.2×10

hQ=10336162

hQ