Question

Jorge wishes to observe the progress of his vacuum pump in evacuating a tall bell jar for the purpose of demonstrating that sound waves do not travel in a vacuum. So, Jorge places a mercury barometer inside the bell jar and follows the height of the mercury column as the pump chugs away. When he observes a height of 8.69 mm, what fraction of atmospheric pressure, expressed as a percentage, has Jorge achieved in his bell jar? The density of mercury is 1.36 × 10 4 kg/m 3 and the standard atmospheric pressure is 1.01 × 10 5 Pa. The acceleration g due to gravity is 9.81 m/s 2 . g

Answer 1

Answer:

1.147 %

Explanation:

$\rho$ = Density of mercury = $1.36\times 10^4\ kg/m^3$

g = Acceleration due to gravity = 9.81 m/s²

h = Height of mercury = 8.69 m

Standard atmospheric pressure = $1.01\times 10^5\ Pa$

6.55 mmHg converting to Pa

$\rho gh\\ =1.36\times 10^4\times 9.81\times 8.69\times 10^{-3}\\ =1159.38504\ Pa$

Dividing air pressure by the above value

$\frac{1159.38504}{1.01\times 10^5}\times 100=1.147\ \%$

The fraction of atmospheric pressure is 1.147 %