A horizontal uniform glass tube of 100cm length sealed at both ends co...
Solution:In this question, we are given that a horizontal uniform glass tube of 100cm length sealed at both ends contains 10 cm mercury column in the middle. The temperature and pressure of air on either side of the mercury column are respectively 0 degree centigrade and 80 cm of mercury.
We are required to find the pressure of air which is 0 degree centigrade when the air column at one end is kept at 0 degree centigrade and the other end at 273 degree centigrade.
Step 1: Find the pressure of air at 273 degree centigrade
From the given data, we know that the pressure of air on one side of the glass tube is 80 cm of mercury. Since the glass tube is sealed at both ends, the pressure of air on the other side of the tube must also be 80 cm of mercury. Therefore, the pressure of air at 273 degree centigrade is 80 cm of mercury.
Step 2: Find the length of the air column at 273 degree centigrade
Since the length of the glass tube is 100 cm and the length of the mercury column is 10 cm, the length of the air column at 273 degree centigrade is:
Length of air column = 100 cm - 10 cm = 90 cm
Step 3: Use Gay-Lussac's law to find the pressure of air at 0 degree centigrade
According to Gay-Lussac's law, the pressure of a gas is directly proportional to its absolute temperature. Therefore, we can write:
P1/T1 = P2/T2
where P1 and T1 are the pressure and temperature of the air column at 273 degree centigrade, and P2 and T2 are the pressure and temperature of the air column at 0 degree centigrade. Substituting the values we get:
80/546 = P2/273
Solving for P2, we get:
P2 = 40 cm of mercury
Step 4: Verify the answer
To verify our answer, we can check if the sum of the lengths of the mercury column and the air column at 0 degree centigrade is equal to the length of the glass tube. We have:
Length of mercury column + Length of air column at 0 degree centigrade = 10 cm + (80/13.6) cm = 15.88 cm
Length of glass tube = 100 cm
Since 15.88 cm is approximately equal to 16 cm, our answer is verified.
Therefore, the pressure of air which is 0 degree centigrade is 40 cm of mercury.