The Relationship
The speed of a wave (like light or sound) is determined by the medium it travels through. Here's the key relationship:
* Speed = Frequency x Wavelength
Let's break down how this applies:
* Frequency (f): The number of wave cycles that pass a point in a given time (usually measured in Hertz - Hz).
* Wavelength (λ): The distance between two consecutive crests or troughs of a wave (usually measured in meters - m).
* Speed (v): How fast the wave is moving (usually measured in meters per second - m/s).
Changes and Their Impact
* Frequency and Speed: For a given medium, the speed of a wave is *constant*. This means if you change the frequency, the wavelength *must* change to compensate and keep the speed constant.
* Higher Frequency: Shorter wavelength
* Lower Frequency: Longer wavelength
* Wavelength and Speed: Similarly, if you change the wavelength, the frequency must change to maintain a constant speed in the same medium.
* Longer Wavelength: Lower frequency
* Shorter Wavelength: Higher frequency
Important Note: The speed of light in a vacuum is a universal constant (approximately 299,792,458 m/s). This means that even though light can change frequency and wavelength as it travels through different mediums, its speed in a vacuum is always the same.
Examples
* Sound: Sound travels faster in solids than in liquids, and faster in liquids than in gases. If you increase the frequency of a sound wave (making it higher pitched), the wavelength will decrease to maintain the same speed in the medium.
* Light: Light slows down when it travels through different mediums like water or glass. This causes the wavelength to decrease, while the frequency remains the same.
Summary
In a given medium, the speed of a wave is constant. Changes in frequency and wavelength are inversely proportional to each other to maintain this constant speed.
