This document provides an overview of physics as a branch of science, the nine major branches of physics, and concepts related to physical quantities and measurement in the International System of Units (SI). It defines physics as the study of matter, energy, and their interactions. The major branches covered are mechanics, heat, light, sound, electricity and magnetism, atomic physics, plasma physics, nuclear physics, and geophysics. It discusses physical quantities, base and derived units, prefixes, and standard notation used in physics.