Q. Define the following characteristics of waves. i) Time Period ii) Frequency iii) Wavelength iv) Wave Speed v) Wave Front

 i) Time Period: The required by one point on a wave to complete one vibration is called Time Period.It is denoted by “T” and its S.I. unit is second (s).

ii) Frequency: The number of waves produced by any source in unit time (1 second) is called frequency. OR The number of waves passing through a point in unit time is called frequency. It is denoted by “f” and its S.I. unit is Hertz(Hz).

or                                                                

iii) Wavelength: The linear distance between two consecutive crests or troughs is called wave length of that wave. OR The linear distance between two consecutive compressions or rarefactions is called wavelength of that wave .It is denoted by “ ” and its S.I. unit is meters(m).

iv) Wave Speed:  The speed by which a wave travels is called wave speed. Its is denoted by “v” and its S.I unit is meter per second (m/s).

Let  is the distance covered by a wave in time “T” so according to the definition of Speed we can write as

             Speed = Distance covered/ Time

                V= λ / T

or          V= λ x 1/T   -----(i)

As we know that

                f = 1/T

Putting in equation (i) we get

                 V=f λ

               so wave speed is equal to the product of frequency and wavelength of that wave.

v) Wave Front: The Wave front is an imaginary line on a wave that joins all points that are in the same phase. A wavefront is usually drawn by joining all wave crests.

There are two types of the wavefront, depending on how the waves are produced, which are concentric circles and plane straight lines.In a ripple tank, a dipper can produce circular waves. These waves have a circular wavefront. In a ripple tank, a plane dipper can produce plane waves. These waves have a plane wavefront.