Modern Physics Formula for NEET 2026 Exam

What are Modern Physics Formulas?

Modern physics talks about new concepts in physics that came after Newton’s time. It mainly deals with two big discoveries: relativity and quantum mechanics. These ideas help us understand things like the photoelectric effect, how atoms work (Bohr’s model), nuclear physics, and radioactivity.

Learning the important Modern Physics formulas for NEET 2026 is effective, as many questions are directly based on these formulas, and knowing them helps you solve problems quickly in the NEET exam. These formulas cover all the important topics like the photoelectric effect, atomic models, nuclear physics, and radioactivity. By memorising the NEET Modern Physics formula list, you can save time during the NEET exam and improve your chances of scoring higher.

NEET 2026 Modern Physics chapters

The modern physics chapters for NEET 2026 focus on topics that came after Newton’s time and are important for the exam. The main chapters you need to study for NEET Modern Physics are:

1. Dual nature of matter and radiation

2. Atoms

3. Nuclei

4. Electronic devices

Modern Physics formula sheet for NEET 2026: Chapter-wise

For the chapters Dual Nature of Matter and Radiation, Atoms and Nuclei, and Electronic Devices, the most important NEET Modern Physics formulas are given. These NEET Modern Physics formula lists are easy to remember and cover all the key concepts you need for NEET. This chapter-wise formula sheet also has Modern Physics equations for NEET along with NEET Modern Physics key formulas, and it will help the students to quickly revise and practice the main points from each topic, making their Modern Physics formulas for NEET preparation easier and more effective.

Dual Nature of Matter and Radiation

The formulas with equations are given below:

1. This formula helps to find the wavelength of a moving particle using its mass and velocity:
   $\lambda = \dfrac{h}{p} = \dfrac{h}{mv}$
   Example: If $v = 10^6$ m/s, $m = 9.1 \times 10^{-31}$ kg, then
   $\lambda = \dfrac{6.63 \times 10^{-34}}{9.1 \times 10^{-31} \times 10^6} = 7.29 \times 10^{-10}$ m

2. This is the formula to calculate kinetic energy using wavelength:
   $KE = \dfrac{h^2}{2m\lambda^2}$
   Example: For $\lambda = 1 \times 10^{-10}$ m,
   $KE = \dfrac{(6.63 \times 10^{-34})^2}{2 \times 9.1 \times 10^{-31} \times (1 \times 10^{-10})^2} \approx 2.4 \times 10^{-18}$ J

3. This is Einstein's photoelectric equation showing energy of incident light:
   $h\nu = \phi + \dfrac{1}{2}mv^2$
   Example: If $\phi = 2$ eV, and $h\nu = 3$ eV,
   $\dfrac{1}{2}mv^2 = 3 - 2 = 1$ eV

4. This gives the relation between threshold frequency and work function:
   $\phi = h\nu_0$
   Example: If $\nu_0 = 5 \times 10^{14}$ Hz,
   $\phi = 6.63 \times 10^{-34} \times 5 \times 10^{14} = 3.315 \times 10^{-19}$ J

5. This relates stopping potential and maximum kinetic energy:
   $eV_0 = \dfrac{1}{2}mv^2_{\text{max}}$
   Example: If $v_{\text{max}} = 10^6$ m/s, then
   $V_0 = \dfrac{1}{2} \times \dfrac{9.1 \times 10^{-31} \times (10^6)^2}{1.6 \times 10^{-19}} \approx 2.84$ V

6. This formula links frequency with wavelength and speed of light:
   $\nu = \dfrac{c}{\lambda}$
   Example: For $\lambda = 500$ nm,
   $\nu = \dfrac{3 \times 10^8}{500 \times 10^{-9}} = 6 \times 10^{14}$ Hz

7. This calculates threshold frequency from work function:
   $\nu_0 = \dfrac{\phi}{h}$
   Example: If $\phi = 2$ eV,
   $\nu_0 = \dfrac{2 \times 1.6 \times 10^{-19}}{6.63 \times 10^{-34}} \approx 4.83 \times 10^{14}$ Hz

8. This formula calculates the wavelength of an electron from accelerating voltage:
   $\lambda = \dfrac{h}{\sqrt{2meV}}$
   Example: For $V = 100$ V,
   $\lambda = \dfrac{6.63 \times 10^{-34}}{\sqrt{2 \times 9.1 \times 10^{-31} \times 1.6 \times 10^{-19} \times 100}} \approx 1.23 \times 10^{-10}$ m

Atoms and Nuclei

1. This gives the radius of an atom’s orbit in Bohr’s model:
   $r_n = \dfrac{n^2 h^2 \epsilon_0}{\pi m e^2 Z} = 0.53,\text{\AA} \cdot \dfrac{n^2}{Z}$
   Example: For hydrogen in 1st orbit ($n=1$),
   $r = 0.53$ Å

2. This gives the energy of an electron in nth orbit:
   $E_n = -\dfrac{13.6 Z^2}{n^2}$
   Example: For $Z=1$, $n=2$,
   $E = -\dfrac{13.6}{4} = -3.4$ eV

3. This gives the speed of an electron in nth orbit:
   $v_n = \dfrac{Z e^2}{2 \epsilon_0 h} \cdot \dfrac{1}{n}$
   Example: In hydrogen ($Z=1$, $n=1$),
   $v = 2.18 \times 10^6$ m/s

4. This gives the wavelength of radiation emitted or absorbed:
   $\dfrac{1}{\lambda} = RZ^2 \left( \dfrac{1}{n_1^2} - \dfrac{1}{n_2^2} \right)$
   Example: $n_2 = 3$, $n_1 = 2$, $Z = 1$
   $\dfrac{1}{\lambda} = 1.097 \times 10^7 \left( \dfrac{1}{4} - \dfrac{1}{9} \right) = 1.523 \times 10^6$ m⁻¹

5. This is the formula for binding energy using mass defect:
   $BE = \Delta m \cdot c^2$
   Example: $\Delta m = 0.0025$ u
   $BE = 0.0025 \times 931 = 2.33$ MeV

6. This formula calculates the mass defect of a nucleus:
   $\Delta m = Zm_p + (A - Z)m_n - M_{\text{nucleus}}$
   Example: For He-4:
   $\Delta m = 2(1.00728) + 2(1.00867) - 4.00260 = 0.0304$ u

7. This shows how the number of nuclei decays with time:
   $N = N_0 e^{-\lambda t}$
   Example: If $\lambda = 0.693$, $t = 1$,
   $N = N_0 e^{-0.693} = \dfrac{N_0}{2}$

8. This formula gives decay constant from half-life:
   $\lambda = \dfrac{0.693}{T_{1/2}}$
   Example: For $T_{1/2} = 10$ days,
   $\lambda = 0.0693$ day⁻¹

9. This gives activity of a radioactive sample:
   $A = \lambda N$
   Example: If $\lambda = 0.1$, $N = 500$,
   $A = 50$ decays/s

Electronic Devices

1. This gives current gain in a transistor:
   $\beta = \dfrac{\Delta I_C}{\Delta I_B}$
   Example: $I_C = 3$ mA, $I_B = 30$ μA
   $\beta = \dfrac{3}{0.03} = 100$

2. This is the ratio of collector to emitter current:
   $\alpha = \dfrac{\Delta I_C}{\Delta I_E}$
   Example: $I_C = 9$ mA, $I_E = 10$ mA
   $\alpha = 0.9$

3. These give the relation between alpha and beta in a transistor:
   $\beta = \dfrac{\alpha}{1 - \alpha} \quad , \quad \alpha = \dfrac{\beta}{1 + \beta}$
   Example: If $\alpha = 0.98$, then $\beta = \dfrac{0.98}{0.02} = 49$

4. This gives average current in full wave rectifier:
   $I_{\text{avg(full wave)}} = \dfrac{2I_0}{\pi}$
   Example: $I_0 = 10$ A,
   $I_{\text{avg}} = \dfrac{20}{\pi} \approx 6.37$ A

5. This gives average current in half wave rectifier:
   $I_{\text{avg(half wave)}} = \dfrac{I_0}{\pi}$
   Example: $I_0 = 10$ A,
   $I_{\text{avg}} = \dfrac{10}{\pi} \approx 3.18$ A

6. These are the efficiency values of rectifiers:
   $\eta_{\text{full wave}} = 81.2%$
   $\eta_{\text{half wave}} = 40.6%$

7. This shows Zener diode maintains constant voltage:
   $V_Z = \text{constant (in breakdown region)}$
   Example: If Zener breakdown at 5.6 V, output remains 5.6 V even if input rises.

8. These are the logic gate formulas:
   $Y_{\text{AND}} = A \cdot B$
   Example: $A = 1$, $B = 1$ → $Y = 1$

9. The OR gate gives a high output (1) if at least one of the inputs is high:
   $Y_{\text{OR}} = A + B$
   Example: $A = 1$, $B = 0$ → $Y = 1$

10. The NOT gate gives the inverse or complement of the input:
    $Y_{\text{NOT}} = \overline{A}$
    Example: $A = 0$ → $Y = 1$

11. The NAND gate gives a low output (0) only when all inputs are high:
    $Y_{\text{NAND}} = \overline{A \cdot B}$
    Example: $A = 1$, $B = 1$ → $Y = 0$

12. The NOR gate gives a high output (1) only when all inputs are low:
    $Y_{\text{NOR}} = \overline{A + B}$
    Example: $A = 0$, $B = 0$ → $Y = 1$

These formulas of Modern Physics for NEET have to be understood so that the students can do well in the exam. With practice and study, students can apply these formulas to solve Modern Physics questions without any difficulty. Revision and practice of these equations from time to time will help the students have a clear idea about Modern physics and perform well in preparation for the NEET 2026 exam.

Are Physics Formulas Enough for NEET 2026?

Important Formulas for NEET 2026 Physics help with many questions that are based on the direct application of formulas, especially in problem-solving and numerical questions. However, just memorising formulas is not enough. To score well, you also need to understand the concepts behind the formulas and know how to apply them in different situations. NEET Physics questions often test your conceptual clarity, so practice using the formulas in various types of problems is important.

What does Modern Physics include in NEET?

Modern Physics in NEET includes topics that were developed after the classical (Newtonian) era. The main chapters are:

• Dual Nature of Radiation and Matter

• Atoms

• Nuclei

• Electronic Devices (Semiconductor Electronics)

Is the Modern Physics Formula Based?

Yes, modern physics in NEET is largely formula-based. Many questions are directly related to the use of specific formulas from topics like the photoelectric effect, Bohr’s model, nuclear physics, radioactivity, and electronic devices. Students are often required to apply these formulas to solve numerical problems and conceptual questions quickly and accurately. However, understanding the underlying concepts is also important, as some questions may test your learn of theory along with formula application.