- What is meant by frequency of sound waves?
- Give the range of frequencies of sound waves that an average human ear can detect.
- A source of wave produces 20 crests and 20 troughs in 0.2 s. The distance between a crest and next trough is 50 cm. Find the
- wavelength
- frequency
- time period of the wave

1.**Frequency** The number of waves produced per second is called the frequency of the wave

2. 20 Hz to 20 kHz

3.

- Since the distance between a crest and next trough is

Therefore, = 50 cm

⇒ λ = 100 cm or 1 m - Distance covered in 20 crests = 20 x 1 = 20 m

∴ Velocity of the wave, v = vλ =

⇒ [∵ t = 0.2 s]

∴ v = 100 Hz

or 1 crest and 1 through = 1 waves

∴ 20 crests and 20 throughs = 20 waves

∴ Frequency = = = 100 Hz - ∴ Time period, T = = = 0.01 s