Physics Class 9 notes for kpk chapter 1 pdf download physical quantities and measurement. PHYSICAL QUANTITIES AND MEASUREMENT Q.1 What is physics? Also, describe its important branches? PHYSICS :> The branch of science which deals with the study of properties, energy, and their mutual relationship is called physics” Some important branches of physics are given below 1. Mechanics:- It deals with the motion of bodies under the action of the force. 2. Heat and thermodynamics:- It deals with the study of nature, properties. and uses of heat energy. And also deals with the transformation of heat energy from one to another form. 3. Optics:- it deals with the prorogation, reflection, refraction, dispersion, and wave properties of light. 4. Electricity and magnetism:- it deals with the study of charges at rest as well as in motion. 5. Atomic physics:- it deals with the structure and properties of an individual atom. 6. Nucleus physics:- it deals