JEE Main · Physics ↓ Falling

Dual Nature of Radiation and Matter appeared 31 times across 3 years — 3.6% of Physics. This question is from de Broglie Wavelength.

Year 2026 2025 2024 Total
Questions 7 16 8 31

A proton of mass mₚ has same energy as that of a photon of wavelength λ . If the proton is moving at non-relativistic speed, then ratio of its de Broglie wavelength to the wavelength of photon is.

Solution & Explanation

Core Logic

Let E represent the identical energy value shared by both particles:

Ephoton = hcλ = E Eₚᵣₒₜₒₙ = p²2mₚ = E p = 2mₚE

Now, expressing the ratio of the proton's de Broglie wavelength to the photon's wavelength:

λₚᵣₒₜₒₙλphoton = h/phc/E = h/ 2mₚEhc/E λₚᵣₒₜₒₙλphoton = Ec 2mₚE = 1c E2mₚ
Step 1: Final Conclusion

The calculated ratio maps to option (3).

Pattern Recognition

Combine the core formulas: λmatter = h 2mE and λlight = hcmathrmE. Dividing them smoothly yields the standard non-relativistic scaling ratio.

Chapter Mix

Class 12 Physics: Dual Nature of Radiation and Matter

Reference Study Guides

More Dual Nature of Radiation and Matter Previous-Year Questions — Page 5

Q8 jee_main_2025_28_jan_evening Wave Particle Duality
Which of the following phenomena can not be explained by wave theory of light? [cite: 52-53]
  • A. Reflection of light
  • B. Diffraction of light
  • C. Refraction of light
  • D. Compton effect

Solution

Core Logic
  • Reflection, Refraction, and Diffraction can all be fully explained using Huygens' principle and wave theory paths [cite: 54, 47, 66].
  • Compton effect involves the scattering of an X-ray photon by an electron, demonstrating explicit momentum conversion. This process requires treating light strictly as localized particle packets (photons) and cannot be captured by continuous classical wave formulations.
Step 1: Conclusion

Hence, the Compton effect is the correct answer as it relies entirely on the particle nature of electromagnetic waves.

Pattern Recognition

Phenomena such as the Photoelectric Effect, Compton Scattering, and Blackbody Radiation serve as absolute foundational evidence for the particle/quantum layout of radiation, while Interference, Diffraction, and Polarization confirm wave configurations.

Chapter Mix

Class 12 Physics: Dual Nature of Radiation and Matter

Q jee_main_2025_29_jan_morning Photoelectric Effect
Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : Emission of electrons in photoelectric effect can be suppressed by applying a sufficiently negative electron potential to the photoemissive substance. Reason (R): A negative electric potential, which stops the emission of electrons from the surface of a photoemissive substance, varies linearly with frequency of incident radiation. In the light of the above statements, choose the most appropriate answer from the options given below:
  • A. (A) is false but (R) is true.
  • B. (A) is true but (R) is false.
  • C. Both (A) and (R) are true and (R) is the correct explanation of (A).
  • D. Both (A) and (R) are true but (R) is not the correct explanation of (A).

Solution

Related Formula
eV₀ = hν - φ₀
Core Logic

Assertion (A) is true because applying a negative stopping potential decelerates the emitted photoelectrons and drops the output current down to zero. Reason (R) is true because the stopping potential V₀ = ((h)/(e))ν - (φ₀)/(e) is linear with frequency ν. However, the linearity of V₀ vs frequency does not explain the physical mechanism behind why a negative potential stops electron emission.

Chapter Mix

Class 12 Physics: Dual Nature of Radiation and Matter

Q jee_main_2025_29_jan_morning de Broglie Wavelength
If λ and K are de Broglie Wavelength and kinetic energy, respectively, of a particle with constant mass. The correct graphical representation for the particle will be :-
  • A.
  • B.
  • C.
  • D.

Solution

Related Formula

λ = h√(2mK)

λ² = ((h²)/(2m)) (1)/(K)
Core Logic

Rearranging the de Broglie equation displays a parabolic relationship when evaluating squared attributes or corresponding axes coordinates. Given standard λ vs 1√(K) layout tracking, it exhibits an upward facing parabolic behavior matching option (2) layout.

Chapter Mix

Class 12 Physics: Dual Nature of Radiation and Matter

Q41 jee_main_2024_01_february_morning de Broglie Wavelength
The de Broglie wavelengths of a proton and an α particle are λ and 2λ respectively. The ratio of the velocities of proton and α particle will be:
  • A. 1 : 8
  • B. 1 : 2
  • C. 4 : 1
  • D. 8 : 1

Solution

Related Formula

de Broglie wavelength relationship to velocity:

λ = (h)/(p) = (h)/(mv) v = (h)/(mλ)
Core Logic

Let mass of proton be mₚ and mass of α particle be m_α = 4mₚ. Given wavelengths: λₚ = λ, λ_α = 2λ.

Set up ratios:

(vₚ)/(v_α) = (m_α)/(mₚ) × (λ_α)/(λₚ)
Step 1: Substitute Ratios
$(vₚ)/(v_α) = 4 × (2λ)/(λ) = 4 × 2 = 8

Hence, the velocity ratio is

Hence, the velocity ratio is $8:1.

Pattern Recognition

Remember the standard mass ratio:

Pattern Recognition

Remember the standard mass ratio: $m_\alpha \approx 4 m_p$. Inversely proportional components mean velocity amplifies significantly.

Chapter Mix

Class 12 Physics: Dual Nature of Radiation and Matter

Q31 jee_main_2024_29_january_evening Photon Theory of Light
Two sources of light emit with a power of 200 W. The ratio of number of photons of visible light emitted by each source having wavelengths 300 nm and 500 nm respectively, will be:
  • A. 1:5
  • B. 1:3
  • C. 5:3
  • D. 3:5

Solution

Related Formula

The power P of a light source emitting n photons per second of wavelength λ is given by:

P = n · (hc)/(λ)

where:

  • h is Planck's constant
  • c is the speed of light
Core Logic

Since both light sources emit with the same power (P = 200 W), we can relate the number of photons emitted per second for each wavelength:

n₁ (hc)/(λ₁) = n₂ (hc)/(λ₂)

Cancelling out the constant terms h and c, we get:

(n₁)/(λ₁) = (n₂)/(λ₂) (n₁)/(n₂) = (λ₁)/(λ₂)

Thus, the ratio of the number of photons emitted is directly proportional to their wavelengths.

Step 1: Substitute the Values

Given values:

  • λ₁ = 300 nm
  • λ₂ = 500 nm
  • Substituting these values into the ratio equation:

(n₁)/(n₂) = (300)/(500) = (3)/(5)

Thus, the ratio is 3:5.

Pattern Recognition

Shortcut: For equal power outputs, the photon emission rate n is directly proportional to the wavelength λ. Therefore, ratio of photons n₁ : n₂ = λ₁ : λ₂ = 300 : 500 = 3:5 directly.

Chapter Mix

Class 12 Physics: Dual Nature of Radiation and Matter

More Dual Nature of Radiation and Matter Questions — jee_main_2025_28_jan_morning

Practice all Dual Nature of Radiation and Matter previous-year questions →

Rankbit System
JEE Physics: Waves (+15.5%) | Electrostatics: Concentric Shells (-29.7%) | Modern Physics: Photoelectric Clones (+34.2%) | Mathematics: Definite Integrals (+18.1%) | Chemistry: Coordination Splitting (-11.4%) | JEE Physics: Waves (+15.5%) | Electrostatics: Concentric Shells (-29.7%) | Modern Physics: Photoelectric Clones (+34.2%) | Mathematics: Definite Integrals (+18.1%) | Chemistry: Coordination Splitting (-11.4%)