Physics Question? Waves and Sound?
The range of human hearing extends from
approximately 20 Hz to 20000 Hz. Find the wavelength for 47.5 Hz at a temperature
of 30.3 ◦C. Assume the velocity of
sound at 0◦C is 331 m/s. Answer in units of m. ANSWER= 7.35 m
Find the wavelength for 1040 Hz at a temperature of 30.3 ◦C. Answer in units of cm. ????????? Please help
- Steve4PhysicsLv 74 years agoFavorite Answer
It depends which method you are meant to use to find speed. Different methods give slightly different answers (some are more accurate than others).
Here are 2 ways:
Method 1: the speed is proportional to the absolute temperature:
0°C = 273.15K
30.3° = 273.15 + 30.3 = 303.45K
Using proportionality: v = 331 x √(303.45/273.15) = 348.88m/s
v = λf
λ = v/f = 348.88/47.5 = 7.34m (close to your required answer)
Method 2. Use the fact that the speed of sound increases by approximately 0.6m/s for each 1°C temperature rise:
Temperature rise = 30.3 - 0 = 30.2°C
New speed = 331 + 30.2x0.6 = 349.12m/s
λ = v/f = 349.12/47.5 = 7.35m (same as your required answer)
So I guess the second method is the one they want.
For part b), the temperature and speeds are the seams as part a) so:
λ = v/f = 349.12/1040 = 0.336m = 33.6cm
- 4 years ago