How much above the surface of earth does the accelration due to gravity reduces by `64%` of its value on the earth. Radius of earth `= 6400 km`.

Explanation

`g' = g - (1)/(100) g = (99)/(100) g (1-(2h)/(R ))`
or `(1 - (1)/(100)) = (- (2h)/(R ))` or `(1)/(100) = (2h)/(R )`
or `h = (R )/(2 xx 100)` or `h = (6400 km)/(2 xx 100) = 32 km`