Every planet revolves around the sun in an elliptical orbit:-
A. The force acting on a planet is inversely proportional to square of distance from sun.
B. Force acting on planet is inversely proportional to product of the masses of the planet and the sun.
C. The Centripetal force acting on the planet is directed away from the sun.
D. The square of time period of revolution of planet around sun is directly proportional to cube of semi-major axis of elliptical orbit.
Choose the correct answer from the options given below:
A. The force acting on a planet is inversely proportional to square of distance from sun.
B. Force acting on planet is inversely proportional to product of the masses of the planet and the sun.
C. The Centripetal force acting on the planet is directed away from the sun.
D. The square of time period of revolution of planet around sun is directly proportional to cube of semi-major axis of elliptical orbit.
Choose the correct answer from the options given below:
- A.B and C only
- B.A and C Only
- C.A and D only
- D.C and D only
Show answer and solution
Correct option: C
Solution
Newton's law of gravitation gives F = GMm/r², so the gravitational force on a planet is inversely proportional to the square of its distance from the sun — statement A is correct. Kepler's third law states T² ∝ a³, where a is the semi-major axis of the elliptical orbit — statement D is correct. Statement B is wrong because force is directly proportional (not inversely proportional) to the product of masses. Statement C is wrong because the centripetal force (gravity) is directed toward the sun, not away from it.
[JEE Main 2023 · 25 Jan · Shift 2]