I am newbie at bitcoin and always i saw a change in bitcoin value. What are the factors that affects the change in bitcoin value? Is it also same like real money? Like if value of Gold decreases then value of US dollar increases and vice versa.

NO NO NO . Bitcoin has a limited supply of 21 million unlike paper money who have billions so if the demand increases the price will also be .Since everyday many people is selling and buying bitcoins thats why the price changes everyday
This article will help you to understand the basics of bitcoin hope it helps
https://www.cryptocoinsnews.com/affects-bitcoin-price/