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Physics

Dual Nature of Radiation and Matter

A Physics chapter of the NEET syllabus, and how to practise it for the computer-based exam.

Exam rules change between cycles. Confirm dates, syllabus and pattern against NTA's official site. We are not NTA.

Weightage: what the paper actually did

Dual Nature of Radiation and Matter carried 5 questions in the NEET 2026 paper. One paper is a data point, not a destiny: NTA moves weight between chapters every cycle, which is why the weightage tables deserve care. The stable facts are the paper's shape: 180 questions, 720 marks, +4 right, −1 wrong.

Sample PYQs from this chapter

Real questions NTA asked from Dual Nature of Radiation and Matter, with the answer and the working. Try before you peek.

Question 1 · NEET 2026

For a metal of work function 6.6 eV6.6\ \text{eV}, which of the following wavelengths of incident radiation does not give rise to the photoelectric effect? (Take Planck's constant as 6.6×10−34 J s6.6 \times 10^{-34}\ \text{J s})
  1. A.100 nm
  2. B.150 nm
  3. C.200 nm
  4. D.50 nm
Answer and explanation

Answer: C

Photoemission requires photon energy hcλ≥W0\dfrac{hc}{\lambda} \geq W_0, i.e. wavelength λ≤hcW0\lambda \leq \dfrac{hc}{W_0}. Here hcW0=6.6×10−34×3×1086.6×1.6×10−19≈187.5 nm\dfrac{hc}{W_0} = \dfrac{6.6\times10^{-34}\times3\times10^{8}}{6.6\times1.6\times10^{-19}} \approx 187.5\ \text{nm}. Any wavelength longer than this cannot eject electrons; 200 nm>187.5 nm200\ \text{nm} > 187.5\ \text{nm}, so it produces no photoelectric effect.

Question 2 · NEET 2026

A photon and an electron, each of 20 eV energy, move in free space. The ratio of linear momentum of electron pep_e to that of photon pPhp_{Ph}, pepPh\frac{p_e}{p_{Ph}} is: [Take speed of light = 3×108 ms−13 \times 10^8\ \text{ms}^{-1}, charge of electron = −1.6×10−19-1.6 \times 10^{-19} C and mass of electron = 9×10−319 \times 10^{-31} kg]
  1. A.2450\frac{2}{450}
  2. B.1250\frac{1}{250}
  3. C.225
  4. D.275
Answer and explanation

Answer: C

A photon's momentum is p=Ec=20×1.6×10−193×108≈1.07×10−26 kg m s−1p = \frac{E}{c} = \frac{20 \times 1.6 \times 10^{-19}}{3 \times 10^8} \approx 1.07 \times 10^{-26}\ \text{kg m s}^{-1}. A non-relativistic electron of the same kinetic energy has p=2mE=2(9×10−31)(3.2×10−18)=2.4×10−24 kg m s−1p = \sqrt{2mE} = \sqrt{2(9 \times 10^{-31})(3.2 \times 10^{-18})} = 2.4 \times 10^{-24}\ \text{kg m s}^{-1}. The ratio is therefore about 225 - a massive particle carries far more momentum than a photon of the same energy, because p∝Ep \propto \sqrt{E} for matter but p∝Ep \propto E for light. NCERT Class 12, Dual Nature of Radiation and Matter.

How to practise Dual Nature of Radiation and Matter

Chapter by chapter, against real past-paper questions, on a screen: NEET is computer based from 2027. Read the chapter once, then attempt its PYQs until your accuracy stops climbing, and let the wrong answers tell you which lines to reread. If the chapter keeps refusing to stick, that has its own guide. There is also a free NEET mini mock with answers.

Nearby Physics chapters

Questions

How many questions did Dual Nature of Radiation and Matter have in NEET 2026?

Dual Nature of Radiation and Matter carried 5 questions in the NEET 2026 paper. Weightage shifts between cycles, so treat it as a probability, not a promise.

Where can I practise Dual Nature of Radiation and Matter PYQs for NEET?

Explore available chapter-wise NEET practice in BrainIt, free until the 2027 exam. Review explanations and track chapter accuracy to guide your revision. Sample questions from this chapter are on this page.

Is Dual Nature of Radiation and Matter important for NEET 2027?

It is part of the Physics syllabus the paper draws from, and NEET 2027 is computer based, so practise it on a screen. Your own accuracy in the chapter matters more than any weightage table: a heavy chapter you already score well on needs less time than a light one you keep missing.

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