The weight of a body on surface of earth is 12.6 N. When it is raised to a height half the radius of earth its weight will be

Options

(a) 2.8 N
(b) 5.6 N
(c) 12.6 N
(d) 25.2 N

Correct Answer:

5.6 N

Explanation:

Weight of body on the surface of earth, mg=12.6 N
At height h, the value of g’ is given by
g’=g (R/R+(R/2))²
=g 4/9
Weight at height, h=mg 4/9
h=12.6×4/9 =5.6 N