Question

The height of mercury column in a barometer in a Calcutta laboratory was recorded to be 75 cm. Calculate this pressure in SI and CGS units using the following data : Specific gravity of mercuty = 13.6, Density of water = ${10}^{3}kg/m^3$, g = $9.8m/s^2$ at Calcutta. Pressure = hpg in usual symbols.

Answer 1

Height, h = 75 cm = 0.75 m

Density of mercury = 13600 $kg/m^3$

$g=9.8m/se{c}^2$

Pressure = hpg

$=\left(0.75\right)\times 13600\times 9.8$

$=10\times {10}^{4}N/m^2$ (approximately)

In C.G.S. units P = $10\times {10}^{4}N/m^2$

$=\frac{10\times {10}^4\times {10}^{5}dyne}{{10}^{4}c{m}^2}$

$=10\times {10}^{5}dyne/c{m}^2$