JEE Main 2024 Physics question
The gravitational potential at a point above the surface of earth is – 5.12 × 10⁷ J/kg and the acceleration due to gravity at that point is 6.4 m/s². Assume that the mean radius of earth to be 6400 km. The height of this point above the earth's surface is:
Answer: (C)
Solution
V = −GM/r and g = GM/r², so r = |V|/g = 5.12 × 10⁷/6.4 = 8000 km. The height above the surface is 8000 − 6400 = 1600 km.