Physics (NTSE/Olympiad)  

5. Sound

Audible, Ultrasonic And Infrasonic Waves

(a) Audible Wave :
The human ear is sensitive to sound waves of frequency between 20 Hz to 20 kHz.This range is known as audible range and these waves are known as audible waves.
Example.Waves produced by vibrating sitar, guitar, organ pipes, flutes, shehnai etc.
(b) Ultrasonic waves :
A longitudinal wave whose frequency is above the upper limit of audible range i.e. 20 kHz, is called ultrasonic wave. It is generated by very small sources.
Example.Quartz crystal
(c) Infrasonic wave :
A longitudinal elastic wave whose frequency is below the audible range i.e. 20 Hz, is called an infrasonic wave. It is generally generated by a large source.
Example. Earthquake.

If you want to give information about online courses to other students, then share it with more and more on Facebook, Twitter, Google Plus. The more the shares will be, the more students will benefit. The share buttons are given below for your convenience.

NTSE Physics (Class X)

NTSE Physics (Class IX)


NTSE Physics Course (Class 9 & 10)

NTSE Chemistry Course (Class 9 & 10)

NTSE Geography Course (Class 9 & 10)

NTSE Biology Course (Class 9 & 10)

NTSE Democratic Politics Course (Class 9 & 10)

NTSE Economics Course (Class 9 & 10)

NTSE History Course (Class 9 & 10)

NTSE Mathematics Course (Class 9 & 10)