The frequency (f) of a wave is defined as the number of oscillations or cycles that occur in one second. The time period (T) of a wave, on the other hand, is the time taken for one complete oscillation or cycle. The relationship between frequency and time period can be mathematically expressed as:

```

f = 1/T

```

or

```

T = 1/f

```

In simpler terms, the frequency and time period of a wave are inversely proportional to each other. This means that as the frequency of a wave increases, its time period decreases, and vice versa.

For example, if a wave has a frequency of 2 Hz, it means that it completes 2 oscillations in one second. The time period of this wave would be 1/2 seconds, or 0.5 seconds. Conversely, if a wave has a time period of 0.5 seconds, its frequency would be 1/0.5 Hz, or 2 Hz.

This relationship between frequency and time period holds true for all types of waves, including sound waves, light waves, and electromagnetic waves. It is an important concept in understanding the properties and behavior of waves.