Wavelength depicted on a graph of displacement vs. Since wavelength is a measurement of length, it is measured in metres. As mentioned before, waves consist of oscillations.
The time taken to complete one oscillation is called the period. Period is often denoted as. If you consider the displacement of an individual point over an interval of time and plot a graph of how the displacement varies as a function of time, then one period is represented by the distance between two peaks or two troughs.
This is shown in the graph shown below. Since period measures an interval of time, it is measured in units of seconds. Period depicted on a graph of displacement vs. The reciprocal of the period is known as the frequency.
That is,. The crest of a wave is sometimes also called the peak. Since wave frequency is the number of waves per second, and the period is essentially the number of seconds per wave, the relationship between frequency and period is.
We can see from this relationship that a higher frequency means a shorter period. Recall that the unit for frequency is hertz Hz , and that 1 Hz is one cycle—or one wave—per second. The speed of propagation v w is the distance the wave travels in a given time, which is one wavelength in a time of one period. In equation form, it is written as. From this relationship, we see that in a medium where v w is constant, the higher the frequency, the smaller the wavelength. See Figure Amplitude corresponds to the loudness of the sound.
However, high frequencies have shorter wavelengths and are hence best reproduced by a speaker with a small, hard, and tight cone tweeter , whereas lower frequencies are best reproduced by a large and soft cone woofer.
These fundamental relationships hold true for all types of waves. As an example, for water waves, v w is the speed of a surface wave; for sound, v w is the speed of sound; and for visible light, v w is the speed of light. The amplitude X is completely independent of the speed of propagation v w and depends only on the amount of energy in the wave.
In this lab, you will take measurements to determine how the amplitude and the period of waves are affected by the transfer of energy from a cork dropped into the water. The cork initially has some potential energy when it is held above the water—the greater the height, the higher the potential energy.
When it is dropped, such potential energy is converted to kinetic energy as the cork falls. When the cork hits the water, that energy travels through the water in waves. Students can measure the bowl beforehand to help them make a better estimation of the wavelength.
Surface earthquake waves are similar to surface waves on water. The longitudinal waves in an earthquake are called pressure waves P-waves and the transverse waves are called shear waves S-waves. These two types of waves propagate at different speeds, and the speed at which they travel depends on the rigidity of the medium through which they are traveling.
During earthquakes, the speed of P-waves in granite is significantly higher than the speed of S-waves. Both components of earthquakes travel more slowly in less rigid materials, such as sediments. For that reason, the time difference between the P- and S-waves is used to determine the distance to their source, the epicenter of the earthquake.
We know from seismic waves produced by earthquakes that parts of the interior of Earth are liquid. In contrast, compression or longitudinal waves can pass through a liquid and they do go through the core. All waves carry energy, and the energy of earthquake waves is easy to observe based on the amount of damage left behind after the ground has stopped moving.
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What is the difference between wavelength and period? Ask Question. Asked 6 years, 5 months ago. Active 6 years, 5 months ago. Viewed 15k times.
Frequency is then the number of cycles in a second. Generally, we don't talk about period when dealing with energy. Wavelength and frequency are what we deal with here because they are in the formula of energy.
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