Physics Waves DUHS 2023
PMDC Verified Question 48 of 125
If the fundamental frequency of vibration of a string fixed at both ends is 50Hz, the fourth harmonic will be:
A
200 Hz
B
150 Hz
C
125 Hz
D
250 Hz
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: 200 Hz
Concept:

A string fixed at both ends produces harmonic frequencies that are pure integer multiples of its fundamental (lowest) frequency.

Formula:

$$ f_n = n f_1 $$

Solution:

  • We are given the fundamental frequency (first harmonic), \( f_1 = 50 \text{ Hz} \).


  • The question asks for the fourth harmonic, meaning \( n = 4 \).


  • Substitute the values: \( f_4 = 4 \times 50 \text{ Hz} \).


  • \( f_4 = 200 \text{ Hz} \).


Why other options are incorrect:

Option B (150) is the 3rd harmonic. Option D (250) is the 5th harmonic.

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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