What are the 5 Major Laws of Physics

What are the 5 Major Laws of Physics

When matric students enter 9th class for the first time, they are officially introduced to the subject of physics. At the introductory level, there are basic physics laws that students must learn, which create the basis for the rest of the subject.

It may seem overwhelming, but these laws are fairly easy to remember as long as students have a strong understanding of their concepts. Learning the concepts behind the basic physics laws will ensure that they score well on the final exams throughout their matric and intermediate years.

So, to help get you started, here are the 5 major laws of physics that you should remember in order to perform well in 9th class physics final exams.


5 Major Laws of Physics


Newton’s Laws of Motion

All 9th class students are familiar with Newton’s 3 laws of motion.

These 3 fundamental laws are extremely important for the rest of the physics course. Very briefly, here are what each of the 3 laws state:


  • First Rule states that an object will remain at rest or in a uniform state of motion unless that state is changed by an external force. 
  • Second Rule states that force is equal to the change in momentum (mass times velocity) over time. In other words, the rate of change is directly proportional to the amount of force applied. 
  • Third Rule states that for every action in nature there is an equal and opposite reaction. 


These laws of motion create the basis for classical mechanics, which is the study of how bodies behave physically under the influence of outside forces.

Conservation of Mass and Energy

This famous law was introduced by Albert Einstein and associates with the equation E = mc^2. This theory forms the basis of relativity, and are briefly explained as follows:


  • Principle of Relativity: The laws of physics are the same for all inertial reference frames. 
  • Principle of Constancy of the Speed of Light: Light always propagates through a vacuum at a definite velocity, which is independent of the state of motion of the emitting body.


The conservation of mass and energy is a fundamental law of physics that all 9th class students should be familiar with. Questions related to this law often appear on final exams, so a conceptual understanding is key.

Law of Universal Gravitation

The universal law of gravitation was introduced by the famous physicist, Sir Isaac Newton, and outlines the theories about gravity and motion. This law is applicable today, and its basic concepts are used throughout the subject of physics. 


His physical law of gravity states that an object attracts another object in direct proportion to their combined mass and inversely related to the square of the distance between them.

Electrostatic Laws

There are two major laws of physics that explain the relationship between electrically charged particles and their ability to create electrostatic force and electrostatic fields. These basic laws of electrostatics form the basis of a very important field of physics, and are stated as follows:


  • Coulomb’s Law: The force between two point charges is directly proportional to the magnitude of each charge and inversely proportional to the square of the distance between their centers. If the objects have the same charge, positive or negative, they will repel each other. If they have opposite charges, they will attract each other.
  • Gauss’s Law: The net flow of an electric field through a closed surface is proportional to the enclosed electric charge. Gauss proposed similar laws relating to magnetism and electromagnetism as a whole.


Electrostatics is an important topic in the 9th class physics syllabus and frequently appears in the past papers. Therefore, it is important for matric students to thoroughly understand these laws, along with the other major laws of physics.


Laws of Thermodynamics

Thermodynamics is another important part of the subject of physics, and in the 9th class syllabus in particular. Here are the basic laws of thermodynamics that matric students should know:


  • The Zeroeth Law of Thermodynamics makes the notion of temperature possible.
  • The First Law of Thermodynamics demonstrates the relationship between internal energy, added heat, and work within a system.
  • The Second Law of Thermodynamics relates to the natural flow of heat within a closed system.
  • The Third Law of Thermodynamics states that it is impossible to create a thermodynamic process that is perfectly efficient.


These are the 5 basic laws of physics that create the basis for the entire subject. 9th class students are expected to have a firm understanding of these basic laws in order to perform well on the final exams. 

For the best practice of applying these basic physics laws, turn to tutoria.pk’s ultimate exam preparation resources. Here you will find complete book notes, lecture videos, and the previous five-year 9th class physics solved past papers for all educational boards in the country, including Rawalpindi Board and all others. 

With the help of the lecture videos and physics solved past papers, matric students should be able to not only remember all the basic laws of physics, but also understand them conceptually and attempt the practical questions that appear on the final exams.

Leave a Reply

Your email address will not be published. Required fields are marked *