Physics Dawn of Modern Physics DUHS 2023
PMDC Verified Question 21 of 52
Which of the following corresponds to the momentum of a photon?
A
\( \frac{h}{\lambda} \)
B
\( h\lambda \)
C
\( \frac{\lambda}{h} \)
D
\( h^2\lambda^{-1} \)
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: \( \frac{h}{\lambda} \)
Concept:

In quantum mechanics, a photon is massless but still carries physical momentum tied to its wave properties.

Formula:

$$ p = \frac{h}{\lambda} $$

Solution:

  • This is directly derived from de Broglie's hypothesis and Einstein's mass-energy equivalence combined with Planck's relation.


  • The momentum \( p \) is universally expressed as Planck's constant divided by the wavelength.


Why other options are incorrect:

Multiplying the values or inverting the fraction produces units that do not correspond to momentum (\( \text{kg m/s} \)).

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

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