NIFT PG 2020 Question Paper with solutions

 One simple physical concept lies behind the formation of the stars gravitational instability. The concept is not new. Newton first perceived it late in the 17 th century. Imagine uniform static cloud of gas in space
  Imagine then that the gas is somehow disturbed so that one small spherical region becomes a little denser than the gas around it so that the small region's gravitational field becomes slightly stronger.
 It now attracts more matter to it and its gravity increases further, causing it to begin to contract. As it contracts, its density increases, which increases its gravity even more, so that it picks up even more matter and contracts even further. The process continue, until the small regions of gas finally forms a gravitationally bound object.