Question

The diagram shows a simple mercury barometer. The mercury level is at a height h when the atmospheric pressure is 100000 Pa.
What is the pressure at P ?

A) 40000 Pa
B) 60000 Pa
C) 100000 Pa
D) 140000 Pa


Please give the solution also​

Answer 1

(D) 14,0000 Pa

Explanation:

Take : $\rho$ : Density of Mercury

1) Since, Atmospheric Pressure is $10^5 Pascal\: (say P_o)$ .

Then,We can say

$P_o-\rho gh=0\\ \\=>h=\frac{P_o}{\rho g}$

2) Then,

We Measure Pressure at Point P, so

$P(req.)=P_o+\rho g(0.4h)\\ \\=P_o+0.4P_o\\ \\=1.4P_o=1.4*10^5 Pascal$

Hence,Option (D) is correct answer.

Note: Pressure at the empty top in tube is 0 since it is assumes to be of vacuum . (No air)

Answer 2

Answer:

answer is b

Explanation:

0.6*100000 = 60000 Pa