NEET (UG) · Physics, Class 12
Dual Nature of Matter and Radiation: NEET PYQ, 2018–2026
Dual Nature of Matter and Radiation (Physics, Class 12) has been asked 16 times in the 7 NEET papers from 2018, 2020, 2021, 2023, 2024, 2025 and 2026: about 2.3 questions a paper, 5% of all Physics questions. It is the 11th most-asked of 20 Physics chapters. NEET 2026 had 3 from it. Last checked 28 October 2026.
Questions per paper
Year by year.
| Year | Questions |
|---|---|
| 2018 | 2 |
| 2020 | 2 |
| 2021 | 2 |
| 2023 | 2 |
| 2024 | 2 |
| 2025 | 3 |
| 2026 | 3 |
From 2021 to 2024 each paper had 200 questions (a Section B with a choice); the others had 180.
Inside the chapter
Topics asked most.
- Photoelectric effect9
- de Broglie wavelength7
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10 Dual Nature of Matter and Radiation questions to practise.
Our own questions, written in the NEET pattern and checked, each with an explanation. Pick an option to see the answer.
Q1 · Physics · Dual Nature of Matter and Radiation
Light of photon energy 5 eV falls on a metal of work function 2 eV. What is the stopping potential?
Answer: (B)
K(max) = hν − φ = 5 − 2 = 3 eV. The stopping potential V₀ satisfies eV₀ = K(max), so V₀ = 3 V.
Q2 · Physics · Dual Nature of Matter and Radiation
A photon and a slow-moving electron have the same wavelength. Which of these quantities is then the same for both?
Answer: (D)
The relation λ = h/p holds for a photon as well as for a material particle, so equal wavelengths mean equal momenta. Their energies differ: the photon has pc, and the slow electron a kinetic energy of p²/2m, which is pc multiplied by v/2c.
Q3 · Physics · Dual Nature of Matter and Radiation
What is the kinetic energy of an electron whose de Broglie wavelength is 1.0 nm? (h = 6.63 × 10⁻³⁴ J s, mass of electron = 9.1 × 10⁻³¹ kg, 1 eV = 1.6 × 10⁻¹⁹ J)
Answer: (D)
p = h/λ = 6.63 × 10⁻³⁴ / 1.0 × 10⁻⁹ = 6.63 × 10⁻²⁵ kg m s⁻¹. K = p²/2m = (6.63 × 10⁻²⁵)² / (2 × 9.1 × 10⁻³¹) ≈ 2.42 × 10⁻¹⁹ J ≈ 1.5 eV. A photon of the same wavelength carries about 1240 eV: an electron and a photon of equal wavelength have equal momenta, not equal energies.
Q4 · Physics · Dual Nature of Matter and Radiation
An electron and a proton have the same kinetic energy. Which has the longer de Broglie wavelength?
Answer: (A)
λ = h/p = h / √(2mK). At the same kinetic energy, the lighter electron has the smaller momentum and therefore the longer wavelength.
Q5 · Physics · Dual Nature of Matter and Radiation
A metal has a work function of 3.3 eV. What is its threshold frequency? (h = 6.6 × 10⁻³⁴ J s; 1 eV = 1.6 × 10⁻¹⁹ J)
Answer: (D)
ν₀ = φ₀/h = (3.3 × 1.6 × 10⁻¹⁹ J) / (6.6 × 10⁻³⁴ J s) = 8 × 10¹⁴ Hz. Light of lower frequency cannot eject electrons from this metal, however intense it is.
Q6 · Physics · Dual Nature of Matter and Radiation
Light of wavelength 400 nm falls on a metal of work function 2.1 eV. The wavelength is then changed to 200 nm. By what factor does the maximum kinetic energy of the photoelectrons increase? (hc = 1240 eV nm)
Answer: (A)
At 400 nm the photon energy is 1240/400 = 3.1 eV, so K_max = 3.1 − 2.1 = 1.0 eV. At 200 nm it is 6.2 eV, so K_max = 6.2 − 2.1 = 4.1 eV. The kinetic energy rises 4.1 times although the photon energy only doubles, because the same work function is subtracted each time.
Q7 · Physics · Dual Nature of Matter and Radiation
An electron starting from rest is accelerated through a potential difference of 400 V. What is its de Broglie wavelength? (Take λ = 1.227/√V nm for an electron accelerated through V volts.)
Answer: (D)
λ = 1.227/√V nm = 1.227/√400 nm = 1.227/20 nm ≈ 0.061 nm. A larger accelerating voltage gives the electron more momentum and so a shorter wavelength.
Q8 · Physics · Dual Nature of Matter and Radiation
Hydrogen gas (molar mass 2 g mol⁻¹) and oxygen gas (molar mass 32 g mol⁻¹) are both at the same temperature. The de Broglie wavelength of each molecule is calculated from its mean translational kinetic energy, (3/2)k_BT. What is the ratio λ(H₂) : λ(O₂)?
Answer: (A)
The de Broglie wavelength is λ = h/p, and p = √(2mK). At the same temperature the mean translational kinetic energy K = (3/2)k_BT is the same for both gases. So λ = h/√(2mK) is proportional to 1/√m. Then λ(H₂)/λ(O₂) = √(m(O₂)/m(H₂)) = √(32/2) = √16 = 4. The lighter hydrogen molecule has the longer wavelength.
Q9 · Physics · Dual Nature of Matter and Radiation
A small photocell is lit by a point source of monochromatic light placed 0.5 m away. The source is then moved to 1.0 m from the cell. Compared with before:
Answer: (D)
The intensity at the cell varies as 1/r², so at twice the distance it is one-quarter, and the saturation current, which is proportional to the intensity, falls to one-quarter. The frequency is the same, so the maximum kinetic energy of the photoelectrons, and with it the stopping potential, stays as it was.
Q10 · Physics · Dual Nature of Matter and Radiation
What is the momentum of a photon of red light of wavelength 660 nm? (h = 6.6 × 10⁻³⁴ J s)
Answer: (C)
A photon has momentum p = h/λ = 6.6 × 10⁻³⁴ / (660 × 10⁻⁹) = 1.0 × 10⁻²⁷ kg m s⁻¹. Its energy is hc/λ, so p is also E/c.
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All 16 real NEET questions from Dual Nature of Matter and Radiation.
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About Dual Nature of Matter and Radiation in NEET.
How many questions come from Dual Nature of Matter and Radiation in NEET?
Dual Nature of Matter and Radiation (Physics, Class 12) has been asked 16 times in the 7 NEET papers from 2018, 2020, 2021, 2023, 2024, 2025 and 2026: about 2.3 questions a paper, 5% of all Physics questions. It is the 11th most-asked of 20 Physics chapters. NEET 2026 had 3 from it.
Which topics of Dual Nature of Matter and Radiation are asked most in NEET?
Photoelectric effect (9), de Broglie wavelength (7), counted over the papers from 2018–2026.
Is Dual Nature of Matter and Radiation important for NEET 2027?
It is in the syllabus in force, so it can be asked. By past papers it ranks 11 of 20 in Physics; use that to decide how much time it gets, not whether to study it.
Where can I solve Dual Nature of Matter and Radiation NEET previous year questions?
On Nikaalle, free: sign up and practise every past NEET question from Dual Nature of Matter and Radiation with an explanation for each, or sit the full papers timed. The ten questions on this page are our own, written in the same pattern.
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