# Two cylinders A and B of equal capacity are connected to each other via a stopcock. A contains a gas at standard temperature and pressure. What is the final pressure of the gas in A and B? - Physics

Numerical

Two cylinders A and B of equal capacity are connected to each other via a stopcock. A contains a gas at standard temperature and pressure. B is completely evacuated. The entire system is thermally insulated. The stopcock is suddenly opened. Answer the following:

What is the final pressure of the gas in A and B?

#### Solution 1

0.5 atm

The volume available to the gas is doubled as soon as the stopcock between cylinders A and B is opened. Since volume is inversely proportional to pressure, the pressure will decrease to one-half of the original value. Since the initial pressure of the gas is 1 atm, the pressure in each cylinder will be 0.5 atm.

#### Solution 2

Since the final temperature and initial temperature remain the same,

therefore "P"_2"V"_2 = "P"_1"V"_1

But P1 = 1 atm, v1 = V, V2 = 2V and P2 = ?

therefore "P"_2 = ("P"_1"V"_1)/"V"_2 = (1xx"V")/"2V"

= 0.5 atm

Concept: Heat, Internal Energy and Work
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#### APPEARS IN

NCERT Class 11 Physics
Chapter 12 Thermodynamics
Exercises | Q 6.1 | Page 316