Physics Dawn of Modern Physics DUHS 2023
PMDC Verified Question 23 of 52
The energy of light is determined by its:
A
Intensity
B
Frequency
C
Amplitude
D
Speed
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: Frequency
Concept:

In classical wave theory, energy was believed to depend on amplitude. Quantum mechanics shattered this by proving the energy of individual light quanta (photons) depends solely on a different parameter.

Formula:

$$ E = hf $$

Solution:

  • Planck and Einstein demonstrated that a single photon's energy is completely dictated by its frequency \( f \).


  • Changing the intensity of light merely changes the number of photons, not the energy of each individual photon.


Why other options are incorrect:

Amplitude and Intensity relate to the total macroscopic brightness, not quantum energy. Speed is constant for all light in a vacuum, so it cannot act as a variable determining energy.

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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