Question

There is no atmosphere on the moon because

• A. it is closer to the earth
• B. it revolves around the earth
• C. the escape velocity of gas molecules is less than their root mean square velocity on the moon
• D. the escape velocity of gas molecules is more than their root mean square velocity on the moon

Answer 1

The correct option is C the escape velocity of gas molecules is less than their root mean square velocity on the moon

The escape velocity on the surface of moon is lesser than the RMS velocity of the molecules of gas at the surface temperature of moon. Therefore, the gas molecules escape and hence moon cannot hold an atmosphere.