# National Standard Examination in Astronomy (NSEA) Solved Paper 2016 Part-1

Q: 1. Two identical stars with mass M orbit around their centre of mass in circular orbit. If radius of the orbit is R and the stars are always diametrically opposite. Consider the following statements:

(i) Their binding force is equal to

(ii) If the stars are heavier and closer, their orbital speed is greater

(iii) The period of the orbit is T=

(iv) The minimum energy required to separate the two stars to infinity is equal to . Select correct statement’s

(A) Only (i) and (ii)

(B) Only (i), (ii) and (iv)

(C) Only (i), (iii) and (iv)

(D) Only (i) and (iii)

Q: 2. The number of natural number such that is a natural number is:

(A) Zero

(B) 2

(C) 50

(D) 5

Q: 3. A monkey is holding onto one end of a rope which passes over a frictionless pulley and at the other end is a plane mirror which has a mass equal to the mass of the monkey. At equilibrium the monkey is able to see her image in the mirror. How does the monkey see her image in the mirror as she climbs up the rope?

(A) The image of the monkey moves with double speed of that of the monkey

(B) The image of the monkey moves with half the speed of that of the monkey

(C) The image of the monkey moves as fast as the monkey

(D) The monkey will not be able to see her image