The value of acceleration due to gravity at a depth of 1600 km is equal to [Radius of earth = 6400 km]

Options

A. `9.8 m s^(-2)`
B. `4.9 m s^(-2)`
C. `7.35 m s^(-2)`
D. `19.6 m s^(-2)`

Answer

C

Explanation

The acceleration due to gravity at a depth below the earth's surface is,
`gd=g((R_(e)-d)/(R_(e)))=g(1-(d)/(R_(e)))=9.8(1-(1600)/(6400))`
`=9.8 xx 0.75 =7.35 m s^(-2)`