If you're a bit confused about different types of waves and the various words used to describe them then you have come to the right place! Waves are a type of energy pathway and are one of the ways how energy can be transferred between energy stores. They do not transport matter, only energy. A wave is essentially an oscillation or a vibration about the restposition,transmittedthrough a medium or a vacuum. Scientists can define the nature and behaviour of these waves using wave property terms, such as amplitude, frequency, period, and wavelength. This article will help you understand the science behind all of these terms. Show
Different types of wavesWaves can be either transverse or longitudinal. The difference depends on the direction of the wave's oscillations. If the oscillations of the wave are perpendicular (right angle) to the direction of travel then the wave is transverse. However, if the oscillations are parallel (same direction) to the wave's direction of travel then the wave is longitudinal.
One example of a transverse wave is the electromagnetic wave, where both the electric and magnetic components of the wave oscillate perpendicular to the direction of travel. Another example can be seen in the diagram above, where a woman is generating a transverse wave in a slinky by vibrating the first coil up and down in the vertical direction. Sound waves are a typical example of a longitudinal wave, where the particles vibrate back and forth parallel to the wave's direction of travel. Another important distinction when discussing waves is whether a wave is mechanical or non-mechanical. The main difference between these two types of waves is if the wave requires a medium to travel through or not. Light can travel through the vacuum of space, which means they are non-mechanical waves: they do not need a medium to travel. All electromagnetic waves are different types of light, encompassing the entire electromagnetic spectrum from radio waves to visible light to gamma rays. Meanwhile, mechanical waves require a medium to travel through. The medium could be any solid, liquid, or gas, such as iron, water, or air. Wave frequencyThe wave frequency is defined as the number of full waves passing an arbitrary point in space every second. The wave period is the time taken for just one full wave to pass a point. Waves with shorter periods will have higher frequencies, as more waves can pass through a point every second. On the other hand, waves with a longer period would have lower frequencies, because fewer waves can pass through a point every second.
Below is a formula used to calculate the frequency and the period of a wave , whereis the frequency of the wave andis the period of the waveIn words, the equation above reads . Question 1 A wave has a period of. What is the wave's frequency? Answer 1 Use the formula relating wave frequency and period . Question 2 Iffull waves of a wave pass an arbitrary point in space in one second, how long is the period of this wave? Answer 2 Iffull waves per second pass a point, we have a wave frequency of. Rearrange the formula given earlier to make the period the subject . Wave amplitudeBelow you can see a simple diagram of a wave. It has several labels that help us identify wave characteristics with wave terms. The wave crest (or peak) is the highest point of oscillation above the rest position, while the trough is the lowest point of oscillation below the rest position. The amplitude of a wave is the maximum displacement between the rest position and its crest. Alternatively, you could measure the maximum displacement between the rest position and the trough as well to get the amplitude of the wave.
The wave amplitude can help inform us about how much energy is in a wave. For example, big (tall) water waves carry more energy than little waves, as you might have experienced yourself. Another example is that an electromagnetic (light) wave with a high amplitude will be brighter than a dimmer, low amplitude wave. Similarly, a sound wave with a high amplitude will be louder than a wave with a lower amplitude. Question 3 The vertical displacement between the crest and trough of a water wave is. What is the wave's amplitude? Answer 3 Wave amplitude is only measured between the crest and the rest position, or the trough and the rest position. The crest and trough of the wave have an equal displacement from the rest position. Therefore, you can divide the displacement between the crest and the trough byto calculate the amplitude of the wave, which is. What is wavelengthYou can also observe that one full wavelength is the length of one complete cycle of the wave, most easily measured either crest-to-crest or trough-to-trough. Both wave amplitude and wavelength are measured in units of distance, with the standard unit as metres. Question 4 The distance between two consecutive wave crests is. What is the total length ofwavelengths? Answer 4 The distance between two consecutive wave crests is equal to one wavelength. The length ofwavelengths means you must multiply this number by, so the answer to the question is . The total vertical displacement between the crest and the trough of a wave is actually a wave property known as wave height, which we measure in. Wave height is a particularly useful concept in coastal science. It is equal to twice the wave amplitude, . Wave speed and phaseThis section will help you to understand the slightly more complex concepts of wave speed, phase, and interference. Other wave properties previously discussed within this article (wave amplitude, wavelength, frequency, and wavelength) should all be understood before continuing. Wave SpeedA very useful equation to know when solving wave problems is the wave speed equation. This equation is used to calculate the speed that a wave is travelling at, using the product of the wave's frequency and its wavelength , . Consider a sound wave travelling from air into the water. The sound waves that aren't reflected at the water's surface will become heavily distorted. The speed of sound in water is approximately, a factor of aboutgreater than in air. This is partially due to the increased density of the water medium compared to air. The sound waves can travel faster in a denser medium as it is easier for particles to bump into each other when oscillating/vibrating. Question 5 A wave has a frequency ofand a wavelength of. What is the wave speed? Answer 5 Convertinto standard units, which reads, then use the wave speed equation to determine the wave speed as follows: . We conclude that the wave speed is. Question 6 A wave propagates through a medium with a wavelength of. In the same medium, what would the wavelength be if a new wave had double its frequency? Answer 6 The speed of a wave is constant in the same medium,. If you double the frequency of a wave then you must halve its wavelength for the speed to remain constant, as follows: . Therefore, the new wavelength would be, or. Wave phase and interferenceMore than one wave can occupy the same position in space at the same time. If two waves coincide when their peaks and troughs match completely, then they are in phase with each other. This is called constructive interference. The two waves superimpose on each other, increasing the total wave amplitude. However, if two waves coincide where the peaks of one wave meet the troughs of another wave, then they are considered to be out of phase. The waves destructively interfere with each other, resulting in zero amplitude.
Properties of Waves - Key takeaways
Which property will increase if you increase the frequency of an electromagnetic wave?An increase in frequency produces a proportional decrease in the wavelength of light with a corresponding increase in the energy of the photons that compose the light. Upon entering a new medium (such as glass or water from air), the speed and wavelength of light is reduced, although the frequency remains unaltered.
What are the properties of electromagnetic waves?All electromagnetic waves: are transverse waves; can travel through a vacuum ; travel at exactly the same speed in a vacuum, the speed of light, 300,000,000 m/s.. transfer energy from one place to another;. can be reflected;. can be refracted .. How are electromagnetic waves affected as the frequency of the waves increases?Because the velocity is constant, any increase in frequency results in a subsequent decrease in wavelength. Therefore, wavelength and frequency are inversely proportional. All forms of EM radiation are grouped according to their wavelengths into an electromagnetic spectrum, seen in Figure 1-3.
Which electromagnetic wave carries the lower frequency?Gamma rays have the highest energies, the shortest wavelengths, and the highest frequencies. Radio waves, on the other hand, have the lowest energies, longest wavelengths, and lowest frequencies of any type of EM radiation.
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Which property of electromagnetic waves must go down as the frequency goes up
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