Laws of Physics
Laws of Physics have a huge impact in stating facts. These laws are derived and proved through empirical observations. Everything that prevails around us has some connection with Physics.
Physicists have derived many laws with proof to illustrate these facts. In other words, the laws of Physics are the kind of explanation that classifies all physical phenomena.
Most of the laws of Physics are not that easy to derive. All scientific researchers are dedicatedly working to establish a law. All these laws given by physicists are under continuous observation by the scientific community and are updated from time to time.
Physicists have explained so many facts in the form of laws to state the phenomena happening around the universe. Here, you will find a brief knowledge of some basic laws of physics and know all about these.
State Hooke's Law
Hooke’s law states that within the elastic extent of a material, the material’s strain is proportional to the material’s stress. The atoms and molecules get a deformation of an elastic material when it gets stretched. It stays stretched for the total time of application of stress. When stress gets removed, they go back to their normal form.
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F = – k. X
Here, F = Force
x = Extended length
k = Spring constant or constant of proportionality
Snell's Law of Refraction
This law states the connection between the angle of incidence and the angle of refraction.
Here is the dedicated Snell’s Law of Refraction:
n1sinӨ1=n2sinӨ2
Gas Laws Physics
Under this section, there are three more laws:
Boyle’s Law
Charles’s Law
Avogadro’s Law
Also, ideal gas law is another part of the gas laws in Physics. These are as follows:
Boyle’s law = PV = k
Charles’s law = V/T = k
Avogadro’s law = \[\frac{v_1}{n_1}\] = \[\frac{v_2}{n_2}\]
Ideal gas law = PV = nRT
Law of Conservation of Energy
This law explains that energy can’t be created and can’t be destroyed. The only possibility is that the energy always changes its state from one to another.
When a system is a closed one, the conservation of energy takes place.
We can calculate a system’s total energy as:
UT = Ui + W + Q,
Where
Q = Heat
W = Work
UT = Total Conservation of Energy
3 Laws of Thermodynamics
The three laws of thermodynamics are mentioned below.
The First Law of Thermodynamics
The Second Law of Thermodynamics
The Third Law of Thermodynamics
Also, another law is associated with thermodynamics, known as the Zeroth law of thermodynamics
Three Laws of Motion by Newton
Newton also stated three laws of motion. They are known as the first, second, and third laws of motion.
First Law: It states that a body at uniform motion or rest will remain in its original state until and unless an external force is applied to it.
Second Law: In short, force is directly proportional to the product of the mass of the body and its acceleration.
Third Law: There is an identical and reverse reaction for every action.
Law of Electrostatics
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Coulomb’s law of electrostatics is the important law of electrostatics. It states that a force F is developed when two different charges, q1 and q2, are placed together with some distance d between them.
The mathematical derivation is:
\[F=\frac{1}{4\pi \xi _0}\frac{qQ}{r^2}=k_e\frac{qQ}{r^2}\]
or, we can write it simply as:
\[F=k\frac{q_1q_2}{d_2}\]
List of all Physics Laws PDF
Here is the list of all Fundamental Laws of Physics:
Carnot’s Theorem
Raman Scattering
Coulomb’s Law
Faraday’s Laws of Electrolysis
Planck Equation
Kirchhoff’s law
Newton’s law of universal gravitation
Electric Potential due to a point charge
Zeroth Law of Thermodynamics
Gauss’ Law
The first law of thermodynamics
Wien's Displacement Law
Joule’s Laws
Radioactive Decay Law
Superposition Principle
Newton’s Laws of Motion
Laws of Thermodynamics
Laws of Friction
Heisenberg Uncertainty Principle
FAQs on Basic Laws of Physics
1. What are the most fundamental laws of physics that students should know?
While there are many laws, several are considered fundamental to understanding the physical world. These can be grouped into key areas:
- Newton's Laws of Motion: These three laws form the foundation of classical mechanics, describing the relationship between an object's motion and the forces acting upon it.
- Laws of Thermodynamics: These laws govern energy, heat, work, and entropy, explaining how energy is transferred and transformed in a system.
- Law of Universal Gravitation: This law describes the gravitational attraction between any two objects with mass.
- Laws of Electromagnetism (Maxwell's Equations): These principles describe the behaviour of electric and magnetic fields.
- Conservation Laws: These include the laws of conservation of energy, mass, and momentum, which state that these quantities remain constant in a closed system.
2. What is Newton's First Law of Motion and why is it also called the law of inertia?
Newton's First Law of Motion states that an object will remain at rest or in uniform motion in a straight line unless acted upon by an external force. It is called the law of inertia because it describes the property of mass called inertia, which is the inherent resistance of any physical object to any change in its state of motion. The more mass an object has, the greater its inertia.
3. What does the Law of Conservation of Energy state, with an example?
The Law of Conservation of Energy states that energy can neither be created nor destroyed; it can only be transformed from one form to another. The total energy in an isolated system always remains constant. For example, when you switch on a light bulb, electrical energy is converted into light energy and heat energy. No energy is lost, it just changes form.
4. Can you explain Coulomb's Law in simple terms?
Coulomb's Law describes the force between two electrically charged particles. In simple terms, it states that:
- The force is stronger when the charges are closer together.
- The force is weaker as the charges move farther apart.
- Like charges (positive-positive or negative-negative) repel each other.
- Opposite charges (positive-negative) attract each other.
This law is fundamental to understanding electrostatics and how charged particles interact.
5. What is Ohm's Law and what is its real-world importance?
Ohm's Law states that the current flowing through a conductor is directly proportional to the voltage across it, provided the temperature and other physical conditions remain unchanged. Its formula is V = IR (Voltage = Current × Resistance). Its real-world importance is immense, as it is a foundational principle for designing and analysing nearly all electrical circuits, from simple household appliances to complex electronic devices like smartphones and computers.
6. How do Newton's Laws of Motion differ from the Laws of Thermodynamics?
The primary difference lies in their domain of application. Newton's Laws of Motion describe the dynamics of objects—how forces cause them to accelerate, move, and interact. They are the foundation of classical mechanics. In contrast, the Laws of Thermodynamics deal with energy, heat, and entropy. They describe the behaviour of energy in large systems, not the motion of a single object, governing everything from engines to chemical reactions.
7. How do basic physics laws apply to an everyday activity like driving a car?
Several physics laws are constantly at play when you drive a car:
- Newton's First Law (Inertia): You feel pushed back into your seat when the car accelerates and lurch forward when it brakes because your body's inertia resists the change in motion.
- Newton's Second Law (F=ma): The force from the engine causes the car's mass to accelerate. More force is needed to accelerate a heavier car.
- Conservation of Energy: The car's engine converts the chemical energy in fuel into kinetic energy (motion), as well as heat and sound energy.
- Laws of Friction: The grip of the tires on the road is due to friction, which is essential for accelerating, braking, and turning safely.
8. Are physical laws absolute and unchanging, or can they be modified?
Physical laws are human-made models designed to describe observed phenomena, and they can be refined or modified as our understanding deepens. While laws like Newton's are extremely accurate for everyday conditions, they have limitations. For example, Newtonian mechanics is not accurate at very high speeds or for very small particles. In these cases, it is superseded by more comprehensive theories like Einstein's Theory of Relativity (for high speeds) and Quantum Mechanics (for atomic and subatomic particles). Therefore, laws are not absolute truths but are our best current descriptions of reality.
9. How does the Law of Conservation of Mass connect both physics and chemistry?
The Law of Conservation of Mass is a unifying principle for both fields. It states that mass in an isolated system is neither created nor destroyed. In chemistry, this means the total mass of the reactants in a chemical reaction must equal the total mass of the products. In physics, this principle is fundamental to classical mechanics. However, modern physics modifies this with Einstein's mass-energy equivalence (E=mc²), showing that mass can be converted to energy in nuclear reactions, which itself is a bridge between the two subjects.
10. Why is the Law of Conservation of Energy considered one of the most important principles in all of science?
The Law of Conservation of Energy is considered so fundamental because of its universal applicability. It holds true across all scales, from subatomic particles to galactic clusters, and in all branches of science, including physics, chemistry, and biology. This universality provides a powerful and reliable framework for analysing any system. Because energy is never lost, only transformed, it allows scientists and engineers to account for all interactions in a predictable way, making it the bedrock for countless technological and scientific advancements.
