# Class 12 Physics Formulas

## Complete List of All Class 12 Physics Formulas: Chapter-wise PDF Download

After Class 10, for students who choose science irrespective of medical or non-medical field, Class 12 Physics is an integral part and somehow becomes a difficult subject to understand. Slowly students, after seeing complex numerical problems, need more understanding and many even start failing the subject.

To understand the concepts, Class 12 Physics Formulas play a significant role not only in the CBSE 2024 board exams but in the further competitive exams as well. The formulas can help students solve the problem directly and in a structured manner. This will also help in clearing the fundamentals of the chapters.

At Educart, the Class 12 Physics formulas list is provided based on NCERT and the latest CBSE pattern to help students find the formula list in one place and be able to score their dream marks.

### General Physics Formulas for Class 12

1. Faraday constant F = 96485 C/mol
2. Bohr magneton µB = 9.27 × 10−24 J/T
3. Planck constant h = 6.63 × 10−34 J.s = 4.136 × 10-15 eV.s
4. Wien displacement constant b = 2.9 × 10−3 m K
5. Rydberg constant R = 1.097 × 107 m−1
6. Molar gas constant R = 8.314 J/(mol K)
7. Mass of proton mp = 1.6726 × 10−27 kg
8. Mass of electron me = 9.1 × 10−31 kg
9. Coulomb constant 1/4πε0 = 8.9875517923(14) × 109 N m2/C2
10. Gravitation constant G = 6.67×10−11 m3 kg−1 s−2
11. Mass of neutron mn = 1.6749 × 10−27 kg
12. Permittivity of vacuum 0 = 8.85 × 10−12 F/m
13. Charge of electron e = 1.602 × 10−19 C

## Class 12 Physics All Formulas Chapter Wise

The Class 12 Physics formulas will help in exam preparation in fast calculations. The formula PDF has it all from simple formulas to the most difficult formulas. The section below has chapter-wise formula links and important topics.

## Chapter 1: Electric Charges and Fields

Physics Chapter 1 Electric Charges and Fields covers all the important topics like Basic Introduction, Conservation of charge, superposition principle, electric field, Coulomb’s law, electric flux, Gauss Theorem, and its applications.

### Electric Charge

#### Properties of Charges

• Quantisation of Charge

q = ± ne

Where n is the number of electrons transferred and e is the basic electron charge.

• Additive Property of Charges

qnet = Σqi

Where, i = 1, 2, 3. . . . n.

• Conservation of Charge/ Law of conservation of charge

→ The total charge of an isolated system remains constant.

→ The electric charges can neither be created nor be destroyed, but can only be transferred from one body to another.

#### Coulomb force between two point charges

Here e0 is known as the permittivity constant of free space and has a value of 8.85 × 10–12 C2N–1m–2. The S.I. unit of force is Newton (N).

#### 1 Coulomb

1C is the charge which when placed 1 m away from another 1C charge exerts a force of 9 × 109N on each other.

As per Newton's third law,

### Electric Field and Electric Dipole

#### Electric Field

Here, Q is known as the source charge, and q is known as the test charge. If the test charge is of 1 C then numerically the field is equal to the force of the source charge on the test charge. Hence, the force can be defined as

#### Superposition of Fields

If multiple charges are around a certain point then the net electric field at a given point is the vector sum of all fields. It is given by,

### Electric Dipole

#### Dipole Moment of the Dipole

The dipole moment of the dipole is given by, p = q (2a)

#### Field on the axis

• For a large distance where r >> a
• In terms of dipole moment, it translates into;

#### Field on the equator

• For a large distance where r >> a
• In terms of dipole moment, it translates into;

### Electric Flux and Gauss's Theorem

#### Continuous Charge Distribution

• Area charge density or surface charge density
• Volume Charge Density

#### Electric Flux

ΦE stands for Electric flux

Unit of  ΦE = unit of E × unit of S

∴ SI unit of Electric Flux = Nm2 C-1 or Vm-1 m2 = Vm

#### Application of Gauss's Theorem

• Field due to infinitely long charged wire
• Field due to an infinite plane lamina
• Field due to a uniformly charged spherical shell

On the surface and outside the shell

Inside the shell

## Chapter 2: Electrostatic Potential and Capacitance

Physics Chapter 2 Electrostatic Potential and Capacitance covers all the important topics like Electric charges, electric potential due to a point charge, and capacitance of a parallel plate capacitor with and without dielectric medium between the plates.

### Electrostatic Potential

#### Potential Due to a Charge

Amount of Work Being Done in Moving The Test Charge

ΔU = UP – UR

= WRP

U = UP – U

### Electrostatics of Conductors

#### Distinguish Between Conductors, Insulators, and Dielectrics

Conductors Insulators Dielectrics
Have free electrons that
can move
throughout the materials.
The electrons are strongly
bound and cannot move
around.
The electrons are strongly
bound and cannot move
around.
Allow the flow of electrons/
charge freely.
Do not allow the flow of
electrons or charges at all.
Electrons or charges can
move a bit such that under
an electric field, the system
can be polarised.
Can be polarised. Cannot polarize in
an electric field.
Can polarize in
an electric field.
Charges can flow Charges are
obstructed
Charges can be
stored.

P = e0 ceE

## Chapter 3: Current Electricity

### Electric Current

#### Ohm’s Law

Below, ρ denotes the resistivity of the material.

#### Current Density

⇒

j = σE

Where σ denotes conductivity which is the reverse of resistivity.

### Cells, EMF, and Internal Resistance

#### Cells in Series

E = E1 + E2

And r = r1 + r

The net EMF is the sum of both EMFs and net resistance is the sum of internal resistances.

ΣI = 0

Σ (E-Ir) = 0

## Chapter 4: Moving Charges and Magnetism

Physics Chapter 4 Moving Charges and Magnetism covers all the important topics like Oersted's experiment, biot-savart law, ampere’s law, moving coil galvanometer, and force on a moving charge in uniform magnetic and electric fields.

### Motion and Force in a Magnetic Field

#### Magnetic Field and Lorentz Force

Where, E = Electric field, B = Magnetic Field. This force is known as the Lorentz Force.

• The unit of the magnetic field is Tesla.
• 1 Gauss = 10–4 Tesla

#### Magnetic Force on a Current-Carrying Conductor

Where j = current density

Pitch = vy T

Where, vy = v||

### Magnetic Field Due to a Current Element

#### Biot-Savart Law

Which can also be written as

Where

#### Magnetic Field on the Axis of a Circular Current Carrying Loop

The field at P due to the current element is given by,

This leads us to two cases

#### Ampere’s Circuital Law

∫ B.dl = μoI

Then, Magnetic Field

## Chapter 5: Magnetism and Matter

Physics Chapter 5 Magnetism and Matter covers all the important topics like bar magnet as an equivalent solenoid, magnetic field intensity due to a magnetic dipole (bar magnet), para-, dia-, and ferromagnetic substances, and the effect of temperature on magnetic properties.

### The Bar Magnet and Magnetic Dipole

#### Field lines of a Bar Magnet

• Magnetic moment m and electric dipole moment p.

### Gauss’s Law of Magnetism

Imagine a small area vector dS such that the flux through it can be stated as

ΦB = ∫B . dS

Unlike electrostatics in magnetism, the flux is zero.

ΦB = 0

### Magnetic Properties of Materials

M = χH

#### Magnetic Susceptibility

B = μ0 (1 + χ ) H = μ0μr H = μH

Where μr = 1 + χ is known as relative permeability.

## Chapter 6:  Electromagnetic Induction

Physics Chapter 6 Electromagnetic Induction covers all the important topics like Faraday's law, induced EMF, and current, Lenz’s law, self, and mutual induction.

### The Basics of Electromagnetism

#### Dimensions of magnetic flux

SI Unit of Magnetic flux

1 Wb = 1 Tm2

Relation Between Weber and Maxwell

1 Wb = 1 Tm2 = 104 × 104 cm2

1 Weber = 108 maxwell

### Inductance

M21 = μon1n2πr12 l

#### AC Generator

E = Eo sin2πνt

Where, ω = 2πv, Eo = NBAω

## Chapter 7: Alternative Current

### Alternating Current and Ac Circuits

#### Kirchhoff's Loop Rule

Instantaneous EMF of the source = Instantaneous potential difference across R.

Im is known as current amplitude.

The sum of instantaneous current values over one complete cycle is zero and the average current is zero.

### AC Voltage Applied to an Inductor

This circuit is purely inductive A.C. circuit.

It is the peak value of A.C.

ωL is known as Inductive Reactance, denoted by XL. SI unit is ohm (Ω).

XL = ωL

The instantaneous power supplied to an inductor is,

So, the average power of the complete cycle is

The average power supplied to an inductor over one complete cycle is zero.

### AC Voltage Applied to a Capacitor

The voltage across the capacitor is given by,

Where the amplitude of oscillating current is, Im = ωCVm

The instantaneous power supplied to the capacitor is,

And the average power of the complete cycle is given by,

### LCR Circuit and AC Devices

#### Phasor-diagram Solution

I = Im sin (ωt + φ)

#### The Power Factor

= VI cos φ

It can also be written as, P = I2 Z cos φ

### Transformer

• In a step-up transformer, Np > Ns, the turn ratio is greater than 1, hence output voltage is greater than the input voltage.
• In a step-down transformer, Ns > Np, the turn ratio is less than 1, hence output voltage is less than input voltage.
• Real transformers are 90-99% efficient. Small energy losses occur in real transformers due to flux leakage, resistance of the windings, eddy currents, or hysteresis.

## Chapter 8: Electromagnetic Waves

Physics Chapter 8 Electromagnetic waves cover all the important topics like areas under simple curves.

## Chapter 9: Ray Optics and Optical

Physics Chapter 9 Ray Optics and Optical covers all the important topics like total internal reflection, linear magnification, power of the lens, and refraction through a prism, microscope, and telescope.

### Reflection of Light by Spherical Mirrors

#### Focal Length of Spherical Mirrors

Here, C is the center of curvature, and F is the Principal Focus of the mirror.

#### Linear Magnification

• When m > 1, an image formed is enlarged.
• When m < 1, an image formed is diminished.
• When m is positive, the image must be erect, i.e., virtual.
• When m is negative, the image must be inverted, i.e., real.

### Refraction

#### Snell’s Law

The refractive index μ of a material is the ratio of the speed of light (c) in vacuum to the speed of light in the medium (v).

### Refraction by Lenses

Magnification by the lens is the ratio of the image to that of the object.

### Lens Formula

#### Power of Lenses

P = P1 + P2 + P3 +.........+ Pn

### Prism and Optical Instruments

δ = i + e – A

#### Refractive Index of Prism

Minimum deviation Dm,

## Chapter 10: Wave Optics

Physics Chapter 10 Wave Optics covers all the important topics like Huygens principle, Interference of light, polarisation, and many more.

### Refraction of Plane Wave

If c represents the speed of light, then

### Refraction at a Rarer Medium

n1sin i = n2 sin r

ic = n2/n1

### Reflection of Plane Wave by a Plane Surface

#### Condition For Constructive Interference

Resultant Intensity at a Point Is Maximum When

cos φ = 1 or φ = 0, 2 p, 4p

path difference is p = 0, λ, 2λ ….. = nλ

### Young’s Double Slit Experiment

Path difference, p = S2P – S1P

Position of bright fringes, for consecutive interference

For central bright fringe n = 0,

For nth bright fringe:

Position of dark fringe, for destructive interference

For the first dark fringe n = 1,

For nth dark fringe

Width of a dark fringe = separation between two consecutive bright fringes

Intensity is proportional to the square of amplitude.

#### The Single Slit

• Calculation of path difference

P = BP – AP = d sin q

• Position of minima

d sin θ1 = λ

• nth dark fringe

d sin qn = nλ, n = 1, 2, 3…

• Position of the nth secondary maximum

## Chapter 11: Dual Nature of Radiation and Matter

Physics Chapter 11 Dual Nature of Radiation Matter covers all the important topics like electron emission and reflection, photoelectric effect, and many more.

### Electron Emission and Photoelectric Effect

#### One electron volt (eV)

1 eV = 1.602 × 10–19 J

Kmax = eVo

## Chapter 12: Atoms

Physics Chapter 12 Atoms covers all the important topics like Bohr’s model and line spectra of the hydrogen atom, the trajectory of α particles, electron orbits, de-broglie’s explanation, and atomic spectra.

### Physics of the Atom

#### Electron Orbit

• the radius of the orbit and electron velocity

• The kinetic energy (K) and electrostatic potential energy (U) of the hydrogen atom

• Total Electron Energy

hν = Ei – Ef

## Chapter 13: Nuclei

Physics Chapter 13 Nuclei covers all the important topics like basic terms and concepts, nuclear binding energy, radioactivity, and radioactive decay.

### Atomic Mass and Composition Of Nucleus

• 1 amu = 1/12 × Mass of the carbon 12-atom
• 1 amu = 1/12 × 1.992678 × 10–26 kg
• 1 amu = 1.660565 × 10–27 kg
• Z = No. of protons in an atom = No. of an electron in an atom = Atomic Number
• N = No. of neutrons in an atom = Neutron number
• A = No. of nucleons in an atom = Mass number = (Z + N) = Total no. of proton and neutron. where Z = Atomic No; A = Mass No; X = Chemical symbol of the element
• Symbolically Representation

### Size Of Nucleus

• The volume of the nucleus is directly proportional to its mass number.
• Density formula

### Mass - Energy and Nuclear Binding Energy

E = mc2

#### Nuclear Binding Energy

ΔEb = Δm × c2

Δm = [Zmp + (A – Z) mn]–M

Binding energy per nucleon is the average energy to extract a single nucleon from the nucleus.

### Nuclear Energy

#### Fission

Let, A = 240 breaks into A1 and A2 of 120

Ebn for A = 7.6 MeV

Ebn for A1 and A2 = 8.5 MeV

## Chapter 14: Semiconductor Electronics: Materials, Devices, and Simple Devices

Physics Chapter 14 Semiconductor Electronics covers all the important topics like classification based on conductivity, intrinsic, and extrinsic metal, and many more.

### Classification of Metals, Conductors, and Semiconductors

#### Classification based on Conductivity

• Metals: High conductivity,

σ = 102 to 108 Sm–1

• Semiconductors: Intermediate conductivity,

σ = 105 to 10–6 Sm–1

• Insulators: Low conductivity,

σ = 10–11 to 10–19 Sm–1

#### Classification based on Energy Bands

Eg = 1.17 eV for Si

Eg = 0.74 eV for Ge

### Intrinsic Semiconductors

• ni = ne = nh

Intrinsic carrier concentration = number of free electrons = number of holes.

• total current is,

I = Ic + Ih; where Ic is electron current under an applied electric force and Ih is hole current

### Extrinsic Semiconductors

• n-Type Semiconductors; ne >> nh
• p-Type Semiconductors; nh >> ne
• The electron and hole concentration in a semiconductor in thermal equilibrium is given by,  ne. nh = ni2

## Applications of Class 12 Physics Formula

The Class 12 Physics formulas aren’t only applicable from the exam’s perspective but it is used in many fields in the real world like scientific research and technology. It will be helpful for every student who especially wants to pursue a career in science research and technology fields. Below are some of the many real-life applications of the Class 12 Physics formulas.

• Fluid mechanics is highly used in the aeronautics department for designing and structuring aircraft. It is also highly useful in trying to understand how many fluids and air behave in motion.
• The medical and clinical instruments along with communication tools use the phenomena of laser stimulation emission.
• Our day-to-day household appliances use the basics of Ohm’s law for designing purposes.
• For the optimization of heat engines and their design, the Carnot efficiency formula in physics is used.

In Physics class 12 all formulas have lots of real-life applications like in nuclear plants, transistors and semiconductors in daily appliances and many more help us in our day-to-day life.

## How to Prepare for the CBSE 2024 Physics Board Exams?

Since CBSE has already notified students regarding the announcement of board exams on January 15, 2024, the preparation must have been started. Although many students still might be wondering how to start preparing for the CBSE 2024 physics board exams, a few tips and tricks might help in getting a kickstart.

• Understand the Class 12 CBSE Physics Syllabus. You may find it at the official site or can download it from here.
• Refer to Class 12 NCERT books and reference books like Concepts of Physics by H.C Verma along with Youtube one-shots to understand the concept. Make sure to make revision notes simultaneously.
• Practice NCERT in-text and exercise questions and use the above-mentioned formulas to solve them quickly.
• Practice the latest pattern questions since CBSE has introduced 50% of questions in the board exams, you can also use additional practice papers introduced by CBSE.
• Attempt Sample Paper Questions from Educart Class 12 Physics Sample Paper book as it covers CBSE-pattern, competency-based questions, PYQs, and follows the latest syllabus.
• Make sure you practice regularly and clear your doubts timely.

You can use memorization techniques like mind maps, Feynman Technique, Colourful memory notes, and many more to study smartly.  The formulas PDFs for Class 12 Physics comprise all the major formulas in the Class 12 CBSE syllabus. Prepare well and practice regularly.

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