Given below are two statements: one is labelled as Assertion A and the other as Reason R.

Question

G1 Physics · Accepted Answer

Escape speed from a body is vₑ = √(2gR). The Moon has both smaller radius and much smaller surface gravity than Earth, so its escape speed is much smaller than Earth's. Gas molecules can therefore escape from the Moon much more easily, which is why the Moon cannot retain a significant atmosphere. Hence both Assertion A and Reason R are true, and R correctly explains A. Option A follows.