Dual Nature of Radiation and Matter — Class 12 MCQs with Answers
Class 12 CBSE Physics · Chapter 11
90 practice questions · 30 Easy · 30 Medium · 30 Hard · Updated
Practise the most important Class 12 CBSE Physics questions from Chapter 11, "Dual Nature of Radiation and Matter". You get 9 timed quizzes made from 90 NCERT-based MCQs, with answers and explanations. The questions are split into 30 Easy, 30 Medium and 30 Hard. Warm up on the basics, then move on to the exam-level questions that set top scorers in CBSE & Maharashtra HSC Board exams, JEE Main, MHT-CET, JEE Advanced and NEET UG apart.
To score well in "Dual Nature of Radiation and Matter", focus on numericals, derivations and applying concepts. Each MCQ here is timed and uses exam-style marking (+4 correct, −1 wrong, 0 skipped). This trains you to stay accurate under time pressure, as real papers need. Every question has a short explanation, so a wrong answer becomes a quick lesson. It is the fastest way to fix gaps before a test.
Use this chapter for focused revision. Start with the Easy set to check your basics on Dual Nature of Radiation and Matter, then move to Medium and Hard to practise applying them. Your accuracy, streaks and XP save automatically. This chapter also adds to your overall Class 12 Physics mastery score. 14 sample questions are solved in full below, with the answer and a worked explanation. Sign in free to start practising.
Key concepts: Dual Nature of Radiation and Matter (Class 12 Physics)
The evidence that radiation and matter both behave as wave and particle: the photoelectric effect with its threshold frequency and stopping potential, the ways it defies classical wave theory, Einstein's photon explanation, and de Broglie's matter waves confirmed by the Davisson-Germer experiment.
- Electron emission
- Electrons can be freed from a metal by heating it, by an applied field, by bombardment, or by light — the last of these being the photoelectric effect.
- Work function
- The minimum energy needed to just free an electron from a metal surface, a property of the metal. It is typically a few electron volts.
- Photoelectric effect
- The instant emission of electrons when light of sufficiently high frequency falls on a metal surface.
- Threshold frequency
- The minimum frequency below which no emission occurs at ALL, however intense the light or however long it shines.
Dual Nature of Radiation and Matter — important questions & MCQs with answers (Class 12 Physics)
14 solved questions from this chapter's difficulty levels, each with its answer and explanation. The other 76 are timed and scored when you sign in.
- Q1Easy
Photoelectric effect Nobel went to:
A.Einstein✓ CorrectB.BohrC.PlanckD.CurieAnswer: A. Einstein
Explanation: Einstein won the 1921 Nobel Prize specifically for explaining the photoelectric effect using light quanta (photons), not for relativity — a common mix-up.
- Q2Easy
de Broglie wavelength:
A.h·cB.hpC.p/hD.h/p✓ CorrectAnswer: D. h/p
Explanation: de Broglie's hypothesis gives λ = h/p = h/(mv) — momentum in the denominator, so mixing this up as h×p is the usual slip.
- Q3Easy
Energy of a photon of frequency ν:
A.h/νB.hν✓ CorrectC.ν/hD.hcAnswer: B. hν
Explanation: Planck's relation E = hν ties photon energy directly to frequency ν, with h as the constant — not ν/h or hc, which mixes in wavelength.
- Q4Easy
Wave nature of matter was proposed by:
A.NewtonB.EinsteinC.BohrD.de Broglie✓ CorrectAnswer: D. de Broglie
Explanation: Louis de Broglie proposed in 1924 that all matter, not just light, has an associated wavelength λ = h/p — extending duality beyond photons.
- Q5Easy
Work function of a metal is:
A.Kinetic energy of photonB.Total electron energyC.Minimum energy needed to eject an electron✓ CorrectD.Photon momentumAnswer: C. Minimum energy needed to eject an electron
Explanation: Work function φ is the MINIMUM energy needed to pull the most loosely bound electron out of a metal surface, not the electron's kinetic or total energy.
- Q6Easy
Davisson-Germer experiment used:
A.Neutrons and leadB.Photons through prismC.Electron diffraction by nickel crystal✓ CorrectD.Protons in waterAnswer: C. Electron diffraction by nickel crystal
Explanation: Davisson and Germer fired electrons at a nickel crystal and saw a diffraction pattern — proof electrons behave as waves, confirming de Broglie's hypothesis.
- Q7Medium
Below threshold frequency, photoelectrons:
A.Increase with intensityB.Are emitted with low energyC.Are not emitted regardless of intensity✓ CorrectD.Always emittedAnswer: C. Are not emitted regardless of intensity
Explanation: If photon energy hν is below the work function (ν < ν₀), a single photon can never eject an electron — piling on more photons (higher intensity) doesn't help.
- Q8Medium
λ of electron accelerated through 100 V:
A.≈ 0.123 nmB.≈ 1.23 nmC.≈ 1.23 ÅD.a and c✓ CorrectAnswer: D. a and c
Explanation: λ = 1.227/√100 nm = 0.123 nm, and since 1 nm = 10 Å, that's also 1.23 Å — both unit forms describe the same wavelength.
- Q9Medium
Max KE of photoelectron:
A.hfB.hf − φ✓ CorrectC.φ − hfD.hf · φAnswer: B. hf − φ
Explanation: Einstein's photoelectric equation rearranges to KE_max = hf − φ: photon energy minus the energy spent escaping the metal surface.
- Q10Medium
λ of electron at 150 V:
A.≈ 1 Å✓ CorrectB.≈ 0.1 ÅC.≈ 10 ÅD.≈ 100 ÅAnswer: A. ≈ 1 Å
Explanation: Using λ(Å) = 12.27/√V, at V = 150 V this gives λ ≈ 12.27/12.25 ≈ 1 Å — remember the constant is 12.27 in ångströms, 1.227 in nanometres.
- Q11Medium
Work function 2 eV. Threshold wavelength ≈
A.1240 nmB.310 nmC.620 nm✓ CorrectD.100 nmAnswer: C. 620 nm
Explanation: Threshold wavelength comes from hc/λ₀ = φ, so λ₀ = 1240 eV·nm ÷ φ = 1240/2 = 620 nm, using the handy hc ≈ 1240 eV·nm shortcut.
- Q12Hard
Intensity of incident light affects:
A.Wavelength of photonB.Their max KEC.Threshold frequencyD.Number of photoelectrons emitted✓ CorrectAnswer: D. Number of photoelectrons emitted
Explanation: Light intensity sets how many photons (and hence electrons) arrive per second, while each electron's energy depends only on frequency — intensity changes count, not KE_max.
- Q13Hard
Wave nature of electrons confirmed by:
A.Millikan oil dropB.Davisson–Germer experiment✓ CorrectC.Rutherford scatteringD.Young's experimentAnswer: B. Davisson–Germer experiment
Explanation: The Davisson–Germer experiment showed electrons diffract off a nickel crystal just like waves, directly confirming the wave nature de Broglie had proposed.
- Q14Hard
Photons of energies 4 eV and 6 eV on metal of φ = 2 eV. Ratio of KE_max values:
A.2:3B.1:2✓ CorrectC.1:3D.3:4Answer: B. 1:2
Explanation: KE_max = hν − φ for each photon: (4−2) eV and (6−2) eV give 2 eV and 4 eV, a ratio of 1:2 — the work function subtracts once from each, not from the ratio directly.
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Start this chapter free →Dual Nature of Radiation and Matter — FAQs
What are the key concepts in Class 12 Physics Dual Nature of Radiation and Matter?+
The evidence that radiation and matter both behave as wave and particle: the photoelectric effect with its threshold frequency and stopping potential, the ways it defies classical wave theory, Einstein's photon explanation, and de Broglie's matter waves confirmed by the Davisson-Germer experiment. Key ideas include Electron emission, Work function, Photoelectric effect, Threshold frequency.
What does Class 12 Physics Chapter 11 (Dual Nature of Radiation and Matter) cover on XamBaaz?+
It has 90 NCERT-based MCQs on "Dual Nature of Radiation and Matter": 30 Easy, 30 Medium and 30 Hard. Together they make 9 timed quizzes, and you never get the same set twice. Every question has an instant explanation. They help you prepare for CBSE & Maharashtra HSC Board exams, JEE Main, MHT-CET, JEE Advanced and NEET UG.
Are these "Dual Nature of Radiation and Matter" questions free to practise?+
Yes. Sign in with Google to practise "Dual Nature of Radiation and Matter" free. Full unlimited access is ₹999/year on a launch offer until 1 December 2026. No chapter is charged separately.
How should I revise "Dual Nature of Radiation and Matter" for the exam?+
Start with the Easy quiz to check your basics, then try Medium and Hard to practise applying them. There are 9 timed quizzes on this chapter, so you can come back for a fresh set instead of one you have seen. Read each explanation, retry the questions you miss, and track your accuracy until it stays high.
Are these "Dual Nature of Radiation and Matter" MCQs available with answers?+
Yes. 14 sample questions are shown here in full, each with the correct option and a step-by-step "Why" explanation. Sign in free with Google to start practising, with instant scoring.
Is there negative marking in the "Dual Nature of Radiation and Matter" quizzes?+
Yes. The timed quizzes use exam-style marking: +4 for a right answer, −1 for a wrong one and 0 for a skip, the same negative marking as JEE Main, JEE Advanced and NEET UG. MHT-CET and CBSE board papers have no negative marking. Our mocks for those are scored their way.
What are the important questions from Dual Nature of Radiation and Matter (Class 12 Physics)?+
The questions that matter most test Electron emission, Work function, Photoelectric effect, Threshold frequency. This page shows 14 solved important MCQs with answers and explanations; all 90 questions on the chapter are available as timed quizzes once you sign in.
Is there an online quiz for Dual Nature of Radiation and Matter?+
Yes — Class 12 Physics Dual Nature of Radiation and Matter has timed online quizzes at Easy, Medium and Hard levels, with instant scoring and a worked explanation on every question. The first quiz on the chapter is free.