**Important
Terms Regarding Wave Motion**

**1) Amplitude (a): **Maximum displacement of a vibrating particle
of medium from its mean position is called amplitude.

**2) Wavelength **\(\left(\lambda \right)\): Wavelength is equal to the distance travelled by the wave during the time in which any one particle of the medium completes one vibration about its mean position (or) distance travelled by the wave in one time period is known as wavelength.

**3) Frequency (n): **Frequency of vibration of a particle is
defined as the number of vibrations complete by particle in one wave in one
second. Units of frequency are hertz (Hz) and per second.

**4) Time Period (T): **Time period of vibration of particle is
defined as the time taken by the particle to complete one vibration about its
mean position. It is the time taken by the wave to travel a distance equal to
one wavelength, Time period \(\left( T \right)=\frac{1}{Frequency\left( n
\right)}\)

**5) Wave pulse: **It is a short wave produced in a medium when
the disturbance created for a short time.

**6) Wave train: **A series of wave pulse is called wave train.

**7) Wave front: **A wave front is a line or surface on which the
disturbance has the same phase at all points. If the source is periodic, it
produces a succession of wave front, all of the same shape. Ripples on a pond
are the example of wave fronts.

**8) Harmonic Wave: **If a travelling wave is a sin (or) cos
function of \(\left( x\pm vt \right)\) the wave is said to be
harmonic of place progressive wave.

**9) The wave equation: **All the travelling waves satisfy a
differential equation which is called the wave equation. It is given by: \(\frac{{{\partial
}^{2}}y}{\partial {{t}^{2}}}={{v}^{2}}\frac{{{\partial }^{2}}y}{\partial
{{x}^{2}}}\), where \(v=\frac{\omega }{k}\)

**10) Wave Velocity\(\left( v
\right)\): **It
is the distance travelled by the disturbance in one time period. It only
depends on the properties of the medium and it independent of time and
position.\(v=n\lambda =\frac{\lambda }{T}=\frac{\omega }{2\pi
}=\frac{\omega }{k}\)

**11) Energy Density: **The energy associated with unit volume of the
medium is defined as energy density.