1) The value of gravititational acceleration g at a height h above the earth's surface is g4 , then (R=radius of earth) A) h=R B) h=R2 C) h=R3 D) h=R4 Answer: Option AExplanation: The value of acceleration due to gravity g at a height h is given by g′=g(ReRe+h)2 [ Symbols have their usual meanings] when, g'= g4 and Re= R So, g4=g(RR+h)2 12=RR+h ⇒ 2R= R+h ⇒ R= h