Question 5. Moon has no atmosphere because (a) It is far away form the surface of the earth (b) Its surface temperature is 10°C (c) The r.m.s. velocity of all the gas molecules is more then the escape velocity of the moons surface (d) The escape velocity of the moons surface is more than the r.m.s velocity of all molecules Answer
The moon's escape velocity is much less than the root mean square (RMS) velocity of gas molecules on the moon. Therefore, the molecules of gas escape from the moon's surface. The gravitational field is weak on the surface of the moon. Hence, the moon doesn't have an atmosphere.
