Answer:
20 Hz, 20000 Hz
0.0166 m, 16.6 m
Explanation:
The minimum frequency that a human ear can hear is 20 Hz
The maximum frequency that a human ear can hear is 20000 Hz.
v = Velocity of sound = 332 m/s
Wavelength is given by
The longest wavelength that can be heard by the human ear is 16.6 m
The shortest wavelength that can be heard by the human ear is 0.0166 m.
Answer:
b) 472HZ, 408HZ
Explanation:
To find the frequencies perceived when the bus approaches and the train departs, you use the Doppler's effect formula for both cases:
fo: frequency of the source = 440Hz
vs: speed of sound = 343m/s
vo: speed of the observer = 0m/s (at rest)
v: sped of the train
f: frequency perceived when the train leaves us.
f': frequency when the train is getTing closer.
Thus, by doing f and f' the subjects of the formulas and replacing the values of v, vo, vs and fo you obtain:
hence, the frequencies for before and after tha train has past are
b) 472HZ, 408HZ