Question

The driver of a car traveling with speed 30 m/sec towards a hill sounds a horn of frequency 600 Hz. If the velocity of sound in air is 330 m/s, the frequency of reflected sound as heard by driver is :

Answer 1

Answer:

The driver of a car traveling with speed 30 m/sec towards a hill sounds a horn of frequency 600 Hz. If the velocity of sound in air is 330 m/s, the frequency of reflected sound as heard by driver is :

ANSWER

As the source is moving towards the hill (the listener), therefore apparent frequency of horn striking the wall is

n

′

=

v−v

s

v

×n

n

′

=

330−30

330

×600=

300

330×600

n

′

=330×2=660Hz

For the reflected sound, driver acts as listener moving towards source (the wall)

∴n

′′

=

v

(v+v

1

)n

′

=

330

(330+30)×660

⇒n

′′

=

330

360×660

=360×2=720Hz

Explanation:

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Answer 2

Answer:

0

Explanation:

because according to law of reflection needs a surface for reflect sound.q