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Q. 4

Expert-verified
Found in: Page 566

### Physics for Scientists and Engineers: A Strategic Approach with Modern Physics

Book edition 4th
Author(s) Randall D. Knight
Pages 1240 pages
ISBN 9780133942651

# 4. The mean free path of molecules in a gas is .a. What will be the mean free path if the pressure is doubled while the temperature is held constant?b. What will be the mean free path if the absolute temperature is doubled while the pressure is held constant?

a) The mean free path will reduce by half when the pressure is doubled, making it in width.

b) As the temperature rises, the mean free path will double to

See the step by step solution

## Step 1: Given Information (Part a)

The mean free path of molecules in a gas is

## Step 2: Explanation (Part a)

Mean free path is given as,

The number density is, however, inversely proportional to it. The number density in an ideal gas, as you have already seen in exercise 1, is inversely proportional to the number density.

The number density of a system is proportional to the pressure and inversely proportional to its temperature, according to the equation. Hence, the mean free path will depend on temperature and pressure in reverse proportion.

## Step 3: Final Answer (Part a)

Hence, the mean free path will reduce by half when the pressure is doubled, making it in width.

## Step 4: Given Information (Part b)

The mean free path of molecules in a gas is .

## Step 5: Explanation (Part b)

Mean free path is given as,

The number density is, however, inversely proportional to it. The number density in an ideal gas, as you have already seen in exercise 1, is inversely proportional to the number density.

The number density of a system is proportional to the pressure and inversely proportional to its temperature, according to the equation. Hence, the mean free path will depend on temperature and pressure in reverse proportion.

## Step 6: Final Answer (Part b)

Hence, As the temperature rises, the mean free path will double to