nuclear physics vs physics

nuclear physics and physics both are nouns.

Word	Noun	Adjective	Verb	Adverb
nuclear physics	Yes	No	No	No
physics	Yes	No	No	No

As nouns, physics is a hypernym of nuclear physics; that is, physics is a word with a broader meaning than nuclear physics:

nuclear physics: the branch of physics that studies the internal structure of atomic nuclei
physics: the science of matter and energy and their interactions

Other hypernyms of nuclear physics include natural philosophy.

nuclear physics (noun)	physics (noun)
the branch of physics that studies the internal structure of atomic nuclei	the science of matter and energy and their interactions
	the physical properties, phenomena, and laws of something