What is its importance of physics?

Answer 1

Physics on the grand scale is the fundamental laws of nature without wihich nothing else could exist. It is also the basic practical science, with engineering being its application.

Without physics you would not have even such simple tools as a lever or weighing balance.

Without physics you would not be able to read your computer screen or look at a photograph or the scenery, or listen to music. You would not have electricity.

Without physics you would not have the computer, the camera or the music... and I don't mean recorded or broadcast but musical instruments themselves.

Without physics there be no YOU... nor anyone else... There would be NOTHING else - including chemistry and Biology (the latter is mainly chemistry anyway).