Which one among the following is true for the speed of sound in a given medium?
- (a)Speed of sound remains same at all frequencies
- (b)Speed of sound is faster at higher frequencies
- (c)Speed of sound is slower at higher frequencies
- (d)Speed of sound is slower at higher wavelengths
Correct — A, the speed of sound remains the same at all frequencies. In a given medium (at fixed temperature and pressure) sound travels at a fixed speed regardless of frequency; changing the frequency changes the wavelength instead, since v = f λ with v constant.
- (b)Faster at higher frequencies — Wrong — in an ideal non-dispersive medium the speed does not increase with frequency; only the wavelength shortens.
- (c)Slower at higher frequencies — Wrong — the speed is independent of frequency; it does not fall as frequency rises.
- (d)Slower at higher wavelengths — Wrong — speed does not depend on wavelength either; v stays fixed while f and λ trade off.
Sound speed in a medium is set by the medium's properties (elasticity and density), not by the source frequency: v = √(B/ρ) in a fluid. Since v = f λ, raising the frequency simply shortens the wavelength proportionally, keeping v constant — which is why music of all pitches reaches you together.
Hold v fixed for a given medium: frequency and wavelength are inversely related (v = f λ). If different frequencies travelled at different speeds, a distant band would sound jumbled.
- In a given medium, the speed of sound is the same for all frequencies.
- v = f λ, so higher frequency means shorter wavelength.
- Sound speed depends on the medium (elasticity, density) and temperature.
- Sound travels fastest in solids, slower in liquids, slowest in gases.
- Thinking higher-pitched sound travels faster.
- Confusing a change in wavelength with a change in speed.
Asked as how the speed of sound depends on frequency in a given medium.
No directly related past PYQ was found.
- practice — not a real PYQ
If the frequency of a sound wave in air is doubled, its speed
- (a)doubles
- (b)halves
- (c)stays the same
- (d)becomes zero
Answer(c) stays the same (the wavelength halves).
- practice — not a real PYQ
The speed of sound is greatest in
- (a)vacuum
- (b)air
- (c)water
- (d)steel
Answer(d) steel (a solid).