Question

define physics branches

Answer 1

Cosmology, astronomy,mechanics... Are some important branches

Answer 2

if you are talking about studying physics in higher then
classical mechanics
quantum mechanics
statistical mechanics
nuclear and particle physics
electronics
solid state physics
condensed matter physics
atomic and molecular physics
mathematical physics
and if you are thinking research field of physics so
theoretical physics
high energy physics
experimental condensed matter physics
quantum field theory
string theory
astrophysics
cosmology
nano science and technology
laser
material science
and many more