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Gravitation — Physics STD 11 Science — Question

Rajasthan BoardEnglish MediumSTD 11 SciencePhysicsGravitation2 Marks
Question
Why does the earth have an atmosphere and the moon does not?
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Answer

The escape velocity from the earth surface is about 11.2km/sec which is greater than the r.m.s. velocity of the air molecules. The escape velocity from the moon's surface is about 2.4km/sec which is less than the r.m.s. velocity of the air molecules. Hence, the earth has an atmosphere and the moon does not.

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