Question

If 'R' is the radius of earth, the height from the surface at which the weight of a body becomes one-fourth of its weight, on the surface of earth is:

• A. 2R
• B. R
• C. R/4
• D. R/2

Answer 1

The correct option is B

R

We know, g = GM / R²

g_h ÷ g = GM ÷ R + h² × R² ÷ GM

or, 1÷4g /g = R² ÷ (R + h)²

R + h ÷ R = 2/1

1 + h÷R = 2

h÷R = 1

h=R