Question

Two identical satellites are at R and 7R away from each surface, the wrong statement is (R - Radius of earth) 

(A) ratio of total energy will be 4 

(B) ratio of kinetic energies will be 4 

(C) ratio of potential energies will be 4 

(D) ratio of total energy will be 4 but ratio of potential and kinetic energies will be 2

Answer 1

Correct option: (D) ratio of total energy will be 4 but ratio of potential and kinetic energies will be 2

Explanation:

Orbital radius of satellites

r₁ = R + R = 2R

r₂ = R + 7R = 8R

PE = [(– GMm) / r], KE = [(GMm) / (2r)], TE = [(– GMm) / (2r)]

(PE₁ / PE₂) = (r₂ / r₁),         

(KE₁ / KE₂) = (r₂ / r₁)                    

(TE₁ / TE₂) =  (r₂ / r₁)

hence

(PE₁ / PE₂) = (KE₁ / KE₂) = (TE₁ / TE₂) = (r₂ / r₁) = (8R / 2R) = 4

hence statement D is wrong.