Hello,

Please check the question once. The value of Gravitational Potential might be -5.4 x 10^7 J kg^-2, because the value given by you gives the error.

We know that,

Gravitational Potential, Vp = -G.M / ( R + h )

Hence, -G.M / ( R + h ) = -5.4 x 10^7........... ( 1 )

Also, g = GM / ( R + h )^2

Hence, GM / ( R + h )^2 = 6............... ( 2 )

Dividing ( 1 ) & ( 2 ), we get,

R + h = 9 x 10^6 m

So, 6400 + h = 9000 km

Hence, h = 2600 km.

Best Wishes.