How are wavelength and frequency affected during reflection?

During reflection, the wavelength and frequency of a wave remain unchanged.

When a wave, such as light or sound, encounters a barrier and is reflected, the properties of the wave including its wavelength and frequency are preserved. This is because reflection involves a change in the direction of the wave, not a change in its speed or other characteristics. The speed of a wave is determined by the medium through which it travels, and since the medium does not change during reflection, neither does the speed. As the speed of a wave is directly related to its wavelength and frequency (speed = wavelength x frequency), these properties also remain constant during reflection.

The wavelength of a wave is the distance between two consecutive points in a wave that are in the same phase, such as two consecutive crests or troughs. The frequency, on the other hand, is the number of complete wave cycles that pass a given point in a certain amount of time. These properties are intrinsic to the wave and are determined by the source of the wave, not by what happens to the wave after it is produced. Therefore, when a wave is reflected, its wavelength and frequency do not change.

This principle is fundamental to the understanding of wave behaviour and is applicable to all types of waves, including light, sound, and water waves. For example, when light is reflected off a mirror, the colour of the light (which is determined by its wavelength and frequency) does not change. Similarly, when sound is reflected off a wall, the pitch of the sound (which is also determined by its wavelength and frequency) remains the same.

In conclusion, reflection changes the direction of a wave, but it does not alter the wave's wavelength or frequency. This is because these properties are determined by the source of the wave and the medium through which it travels, neither of which are affected by reflection.