Question

Match list-I with list-II:

List-I	List-II
(A) Kinetic energy of planet	$- \frac{GMm}{a}$
(B) Gravitational Potential energy of Sun-planet system	$- \frac{GMm}{2a}$
(C) Total mechanical energy of planet	$\frac{GM}{r}$
(D) Escape energy at the surface of planet for unit mass object	$- \frac{GMm}{2a}$

(Where a = radius of planet orbit, r = radius of planet, M = mass of Sun, m = mass of planet) Choose the correct answer from the options given below:

• A. (A) – II, (B) – I, (C) – IV, (D) – III
• B. (A) – III, (B) – IV, (C) – I, (D) – II
• C. (A) – I, (B) – IV, (C) – II, (D) – III
• D. (A) – I, (B) – II, (C) – III, (D) – IV

Answer 1

Answer: (A)

(A) – II, (B) – I, (C) – IV, (D) – III

Answer 2

The kinetic energy (KE) of a planet is given by:

$\text{KE} = \frac{1}{2} mv^2 = \frac{GMm}{2a}$

The gravitational potential energy (PE) of the Sun-planet system is:

$\text{PE} = -\frac{GMm}{a}$

The total mechanical energy (TE) of the planet is:

$\text{TE} = \text{KE} + \text{PE} = -\frac{GMm}{2a}$

Escape energy at the surface of the planet for a unit mass object is given by:

$\text{Escape Energy} = \frac{Gm}{r}$