Question

Choose all correct statements about Brownian motion

Select one or more:

a.

Fluctuations in the number and momentum of molecules hitting the dust particle from different directions cause the dust to move.

b.

Each gas molecule has its own temperature.

c.

Each gas molecule has exactly the same kinetic energy

d.

Collisions are elastic and energy and momentum are conserved

Answer 1

Answer: The correct statements about Brownian motion of gas molecules are .

a.

Fluctuations in the number and momentum of molecules hitting the dust particle from different directions cause the dust to move.

d.

Collisions are elastic and energy and momentum are conserved.

Explanation:

At a certain temperature all the gas molecules have same temperature. As the gas molecules have different speed so they have different kinetic energy . So options b and c are not correct.

The cause of motion of a dust particle in a gas medium is due to the Fluctuations in the number and momentum of molecules hitting the dust particle from different directions and the collision is elastic and momentum and energy are conserved. So statement a and d are correct.  

Thank You.