the wood of
log, explain the reason. 6. While a flying mosquito produces vibrational sound from its wings, but there
is no such sound produced in the case of bird-Explain ? 7. Calculate the minimum distance between the
source of transient sound and the reflector for producing echo: 8. Write down three differences
between musical sound and noise.
3 marks
F. Numerical Problems:
1. A sound wave has a frequency of 4MHz and velocity of 1.7 km/s. Calculate the wavelength of the
wave. [1MHz = 106 Hz]. 2. Two tuning forks of frequencies 256 Hz and 192 Hz respectively are vibrated in
air. If the wavelength of second is 1.67m, calculate the wavelength produced by the first. 3. A person fires
a gun and hears the echo from a distant cliff after 5 sec. Find the distance of the cliff from the person.
Given, velocity of sound = 340 m/s. 4. A person fires a gun from a position between two parallel steep
mountains and successively hears two echos, one 1.5 sec and the other 2.5 sec after firing. What is the
distance separating the two mountains ? Velocity of sound in air = 345 m/s. 5. Find the minimum
distance of a reflecting surface which produces a clear echo of a sound consisting of 3 syllables. Given
the velocity of sound = 345 m/s.
Ans. 1. 0.425 mm 2. 1.25 m 3. 850 m 4. 690 m 5. 103.5 m.
Solve​