The specifications of my system are:
Intel core i5-7200U upto 3.1 ghz
8 gb ram
1 TB HDD
2gb NVidia graphics card
I am using UBuntu 18.10 along with windows 10. Any reasons ??
Programs like google chrome also loads slower on ubuntu whereas it opens quicky on windows 10.
That’s the standard behaviour with Windows 10, and a problem with Linux. The battery also drains faster with Ubuntu than with Windows 10, but no idea why. Got to live with it, I suppose. 
This has been discussed-to-death in our support venues https://community.ubuntu.com/t/finding-help/712 so I’ll refer you to those threads.
This site is appropriate for discussing real strategies to speed loading an boot…once you figure out a few. Ubuntu does not have a “load slowly for no reason” setting that you can simply disable.