Physics Waves KU 2024
PMDC Verified Question 9 of 125
What happens when two waves of the same frequency and amplitude meet in phase?
A
They cancel each other out resulting in a destructive interference
B
They combine to from a wave double the amplitude, resulting in constructive interference
C
The produce a wave with zero amplitude, resulting in constructive interference
D
They produce a wave with zero amplitude as the individual waves
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: They combine to from a wave double the amplitude, resulting in constructive interference
Concept:

The Principle of Superposition governs how wave displacements interact when occupying the same space.

Solution:

  • When waves meet "in phase," it means their crests arrive at the exact same point simultaneously (as do their troughs).


  • According to superposition, their individual displacements algebraically add up.


  • Since they have identical amplitudes (\( A \)), the crests merge to create a super-crest of amplitude \( A + A = 2A \).


  • This profound amplification is formally called constructive interference.


Why other options are incorrect:

Option A describes waves meeting entirely out-of-phase (destructive interference). Options C and D contain internal contradictions (zero amplitude cannot be constructive).

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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