Define the ‘frequency’ and ‘time-period’ of a wave. What is the relation between the two?
Answer
The number of complete waves (or cycles) produced in one second is called frequency of the wave. The time required to produce one complete wave (or cycle) is called time-period of the wave. The time taken to complete one vibration is called time-period. Relation between time-period an frequency of a wave is: $\text{Frequency}=\frac{1}{\text{time period}}$
Name the characteristic of sound which can distinguish between the ‘notes’ (musical sounds) played on a flute and a sitar (both the notes having the same pitch and loudness).
What conclusion can be obtained from the observation that when the prongs of a sound making tuning fork touch the surface of water in a beaker, the water gets splashed?
Answer
The conclusion from the observation is that the prongs of tuning fork are vibrating, and the vibrating prongs carry energy which gets transmitted to surrounding medium.
If $20$ waves are produced per second, what is the frequency in hertz$?$
Answer
The frequency in hertz is equal to the number of waves produced per second. In this case, $20$ waves are produced per second, so the frequency of sound waves is $20$ hertz.
Can we hear $(a)$ infrasonic waves $(b)$ ultrasonic waves$?$
Answer
No, we cannot hear infrasonic waves and ultrasonic waves. That’s because the frequencies of both these waves fall beyond the human audible range of frequencies.