The acceleration due to gravity at a height 1 km above the earth is the same as at a depth d below the surface of earth. Then :
Answer & explanation
Correct answer: option 1
Above the surface :
g' = g (1 - \(\frac{2h}{R_e}\))
\(\Delta g\) = g \(\frac{2h}{R_e}\)
Below earth surface :
g' = g (1 - \(\frac{d}{R_e}\))
\(\Delta g\) = g \(\frac{d}{R_e}\)
⇒ d = 2h = 2 x 1 km = 2 km