Q.

The height in terms of radius of the earth (R), at which the acceleration due to gravity becomes g9, where g is acceleration due to gravity on earth's surface, is _____ .       [2026]

1 3R  
2 22R  
3 2R  
4 4R9  

Ans.

(3)

gh=g(1+hR)2

g9=g(1+hR)2

1+hR=3⇒h=2R