The height of the point vertically above the earth's surface, at which acceleration due to gravtiy becomes 1% of its value at the surface is (Radius of the earth =R)

Options

A. 9R
B. 8R
C. 11R
D. none of these

Answer

A

Explanation

Acceleration due to gravity at a hight h from earth surface `=(GM)/((R+h)^(2))`
Now, `(GM)/((R+h)^(2))=1/100(GM)/((R)^(2))`
`rArr h=9R`