question_answer

 (a) What is meant by frequency of sound waves? (b) Give the range of frequencies of sound waves that an average human ear can detect. (c) 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 (i) wavelength                                   (ii) frequency (iii) time period of the wave 

Answer:

   (a) Frequency The number of waves produced per second is called the frequency of the wave.     (b) 20 Hz to 20 kHz                        (c) (i) Since the distance between a crest and next trough is Therefore cm (Given) cm or 1 m (ii) Distance covered in 20 crests = 20 x 1 = 20 Velocity of the wave,   or 1 crest and 1 trough = 1 wave 20 crest and 20 trough = 20 waves Frequency (iii) Time period ,