Introduction to Waves and Sound

This set covers the fundamental definitions, types, and common properties of waves as described in the lecture notes.

Wave

A periodic and regular disturbance in a medium which does not cause any flow of material but causes the flow of energy and momentum from one point to another.

Mechanical waves

Waves for which a material medium is essential for propagation, such as water waves, waves along a stretched string, seismic waves, and sound waves.

EM waves

Waves generated due to periodic vibrations in electric and magnetic fields that can propagate through material media, though a medium is not essential for their propagation.

Matter waves

Waves associated with any object if it is in motion, which are studied in quantum mechanics.

Travelling or progressive waves

Waves in which a disturbance created at one place travels to distant points and keeps travelling unless stopped by some external agencies, transferring energy from one point to another.

Amplitude ($A$)

The largest displacement of a particle of the medium through which the wave is propagating, from its rest position; measured in metre ($m$) in SI units.

Wavelength ($\lambda$)

The distance between two-successive particles which are in the same state of vibration; measured in metre ($m$).

Period ($T$)

The time required to complete one vibration by a particle of the medium; measured in seconds ($s$).

Double periodicity

The property of wave motion where it repeats itself at equal intervals of time (periodic in time) and the form of the wave repeats at equal distances (periodic in space).

Frequency ($n$)

The number of vibrations performed by a particle during each second, measured in hertz ($Hz$). It is the reciprocal of the time period: $n = \frac{1}{T}$.