Question

29. An object is vibrating 4200 times a minute. If velocity of sound is 330 m/s. Calculate :
(a) Frequency :
(b) Wavelength :​

Answer 1

Answer:

Answer

(i) Frequency of vibration is defined as number of vibration per second ,

so , frequency , f=number of vibrations/time in second =7200/60=120Hz ,

(ii) Now given , v=360m/s and f=120Hz

by , v=fλ ,

or λ=v/f=360/120=3m

Answer 2

Answer:

a) 70 Hz

b) 4.71 m (approx.)

Explanation:

Given:

• No. of times the object is vibrating = Frequency (f)  = 4200 times/minute

• Velocity of sound (V) = 330 m/s

To find:

• Frequency (f)

• Wavelength (λ)

Method to find:

To find the frequency,

1 minute = 60 seconds

⇒ 4200 times/minute = (4200/60) times/second

⇒ 70 times/second = 70 Hz

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To find the wavelength,

V = fλ

⇒ 330 = 70 * λ

⇒ λ = 330/70

⇒ λ = 4.71428571429 m ≈ 4.71 m