JEE Main 2022 · 24 Jun · Shift 1 · Physics Q40

PhysicsSingle correct+4 / -1Question 40 of 90

The approximate height from the surface of earth at which the weight of the body becomes $\dfrac13$ of its weight on the surface of earth is :

[Radius of earth $R=6400$ km and $\sqrt3=1.732$ ]

3840 km

4685 km

2133 km

4267 km

Answer and worked solution

Official answer: B

Gravity with height. $g_h=\dfrac g{(1+h/R)^2}=\dfrac g3$ , so $1+\dfrac hR=\sqrt3$ .

Height. $h=(\sqrt3-1)R=0.732\times6400\approx4685$ km.

(B)

Topics:Variation of g

JEE Main 2022 · 24 Jun · Shift 1, Physics question 40