Physics Waves ETEA 2023
PMDC Verified Question 42 of 125
The square root of the ratio of elasticity to mass density is equal to:
A
Force
B
Product of frequency and wavelength
C
Co-efficient of viscosity
D
Refractive index
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: Product of frequency and wavelength
Concept:

The generic formula for the velocity of any mechanical wave through a medium depends on its elastic and inertial properties.

Formula:

$$ v = \sqrt{\frac{E}{\rho}} \quad \text{and} \quad v = f \lambda $$

Solution:

  • The expression "square root of the ratio of elasticity (\( E \)) to mass density (\( \rho \))" is precisely the formula for Wave Velocity (\( v \)).


  • According to the universal wave equation, wave velocity is also equal to the product of its frequency (\( f \)) and wavelength (\( \lambda \)).


  • Therefore, \( \sqrt{E/\rho} = f\lambda \).


Why other options are incorrect:

Options A, C, and D are entirely different physical quantities with vastly different dimensional units. None of them evaluate to \( m/s \).

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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