A simple barometer is constructed using a liquid \(Q_{1}\) of density 16.2\(g/cm^{3}\). Calculate the least lenth of the tube to be used to measure pressure of 1.5atm. [Density of mercury = 13.6\(g/cm^{3}\), 1atm = 76.0 cm of Mercury]
A. 1358mm B. 957mm C. 760mm D. 638mm
Correct Answer: D
Explanation
Let \(h_{Q}\) and \(\rho_{Q}\) be the least length and the density of \(Q_{1}\) while \(h\) and \(\rho\) are the length and density of mercury respectively. \(h\times \rho \times g = h_{Q} \times \rho_{Q} \times g\) \(76cm \times 13.6 \times 10 = h_{Q} \times 16.2 \times 10\) \(h_{Q} = \frac{76\times13.6\times10}{16.2\times10}\) \(h_{Q} = \frac{10336}{162}\) \(h_{Q} \approxeq 63.8cm = 638mm\)
