Question

Coefficient of viscosity of a gas:

• A. increases with increase of temperature
• B. decreases with increase of temperature
• C. remains constant with increase of temperature
• D. may increase or decrease with increase of temperature

Answer 1

The correct option is A

increases with increase of temperature

The explanation for the correct option:

In the case of option A,

The coefficient of viscosity is a measure of the fluid's resistance to flow.

Mathematical representation:

Co-efficient of viscosity, $\mathrm{\eta }=\mathrm{F}.\frac{\mathrm{d}}{\mathrm{A}}.\mathrm{V}$

Here,

$\mathrm{F}$ is the tangential force.

$\mathrm{d}$ is the distance between two layers of liquid skidding each other.

$\mathrm{V}$ is the velocity.

$\mathrm{A}$ is the area.

1. Gas viscosity is generally lower than liquid viscosity.
2. Fluidity is the inverse of viscosity.
3. As a result, a fluid with a high viscosity has poor fluidity.
4. As temperature rises, gas molecules gain speed and collide more frequently while losing their energy and thus increasing viscosity.
5. As a result, the coefficient of viscosity of a gas increases as temperature rises.

Therefore, the coefficient of viscosity of a gas increases with the increase in temperature.

Hence, option A is the correct answer.