Question

Q.28. (A) Distinguish between musical sound and noise. (B) A man standing between two parallel cliffs fires a gun. He hears two echos one after 2 second and the other after 4 second. What is the distance between the cliffs if the velocity of sound is 330 m/s?​

Answer 1

(A)

MUSIC

• It is formed by periodic vibration or by formation of periodic waves.
• It is regular and pleasant to ears.
• The sound  level is comparitvely low but auidible.
• The wavelength and amplitude remains constant.

NOISE

• It is formed by irregular vibration of irregular waves.
• It is harsh and unpleasant to ears.
• The sound level is really high.
• The wavelength and amplitude varies .

(B)

For distance from first cliff

First sound is heard in 2 sec.

Since the medium through which light is travelling is same therefore

Speed of sound = 330 m/s

$SPEED=\dfrac{2 \times Distance}{Time}$

$Distance = \dfrac{Speed \times Time}{2}$

$Distance = \dfrac{330 \times 2}{2}$

Distance for first cliff = 330 m

For distance from second cliff

Second sound is heard in 4 sec.

Since the medium through which light is travelling is same therefore

Speed of sound = 330 m/s

$SPEED=\dfrac{2 \times Distance}{Time}$

$Distance = \dfrac{Speed \times Time}{2}$

$Distance = \dfrac{330 \times 4}{2}$

Distance for first cliff = 660 m

Total distance bwteen both the cliifs will be 330+660=990 m