Physics Waves DUHS 2022
PMDC Verified Question 65 of 125
A sound waves travels from one medium to another, which one of the following characteristics of sound remain unchanged?
A
Amplitude
B
Velocity
C
Pitch
D
Quality
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option C: Pitch
Concept:

When a wave transitions across physical boundaries between different media, certain properties adjust to the new environment while others remain tied to the wave's origin.

Solution:

  • Frequency (Pitch) is fundamentally determined by the oscillating source that created the wave. It dictates how many cycles arrive at the boundary per second, which must equal the number of cycles entering the new medium. Thus, it remains unchanged.


  • Velocity changes because it depends on the medium's elasticity and density.


  • Wavelength changes proportionally with velocity (\( \lambda = v/f \)).


Why other options are incorrect:

Velocity and wavelength adapt to the new medium. Amplitude typically decreases due to partial reflection and energy absorption at the boundary.

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