Wavelength and Frequency (Simplified) - Online Tutor, Practice Problems & Exam Prep

Light energy travels as electromagnetic radiation, characterized by wavelength (λ) and frequency (ν). Wavelength is the distance between consecutive crests or troughs, measured in meters, while frequency indicates the number of waves per second, expressed in Hertz (s^-1). The speed of light (c) is approximately 3.00 × 10⁸ m/s. Frequency and energy are directly proportional, while frequency and wavelength are inversely related, meaning higher frequency results in shorter wavelength and greater energy. Understanding these relationships is crucial for grasping electromagnetic radiation concepts.

Wavelength and Frequency (Simplified) Concept 1

Hey everyone. So, in this video, let's take a look at the idea of Wavelength and Frequency. Now, we're going to say that light energy can travel through space as electromagnetic radiation in the form of particles or waves. Within the scientific community, we can talk about light energy. Some theorize it as photons, individual light particles that travel through space. Others see it not as individual particles, but a group of particles traveling together as a wave. In either case, we're going to say in the vacuum of space, light moves at a speed of 3.00×108 meters per second. This is called the speed of light.

Now, here we're going to say in terms of a wave, the top of the wave is called the crest, and the bottom of the wave is called a trough. If we take a look here, we have our waves being illustrated here. Again, remember, the top of the wave is the crest. The bottom of it is a trough. This here represents the origin, but we kind of cut through it.

Now with this idea of a wave, we have wavelength and frequency. Wavelength uses the Greek symbol, lambda, which looks like this. It's the distance from one crest or trough of a wave to the next. It's expressed in units of meters. So if we're talking the distance from one crest to another crest, that distance, that is our wavelength, typically in meters. Overlooking from the distance from one trough to another trough, that's also a wavelength as well.

Frequency uses the Greek symbol of mu, which kind of looks like a v, a different form of v. The number of waves you have per second, it relates to frequency. Here, we're going to say it's expressed in units of s-1 or Hertz. In this image, we're starting here at the origin going to the crest down to our trough, which represents a wave. And then we have another one. In this image, we have around, 2.5 waves being depicted. We're going to say the number of waves we get within a second, that is our frequency. So we can say that this entire image, we can relate that to frequency.

Alright. So, again, remember, light can travel as either individual photons or a wave of photons. In either case, we're still talking about the speed of light in terms of how light travels, and we're talking about these ideas of wavelength and frequency. Wavelength is the distance from one crest to another or one trough to another, and frequency is how many waves you can get within a given second. Right? So keep these terms in mind as we discuss more about electromagnetic radiation.

Wavelength and Frequency (Simplified) Example 1

So here it says, based on the images given below, which electromagnetic wave has the highest frequency? So remember, frequency is how many waves we can get per second. So if we were to look, we'd say that from this origin point to this origin point represents one wave. Here, this would be a second wave, so here's 1 wave, 2 waves, 3 waves, 4 waves, 5 waves. This one here would be 1 wave, 2 waves, and then 2.5 waves. Then finally here we get 1, 2, 3, 4, 5, 6, 7, and 8. You could also eyeball it and see, like, for sure the image 3 would have the most amount of waves per second, and therefore would have the highest frequency.

Wavelength and Frequency (Simplified) Concept 2

So remember when looking at light energy in terms of a wave, we have wavelength and frequency. And with these two terms, we have relationships that can be created. We're going to say at a fixed speed, the frequency of a light wave is inversely proportional to wavelength and directly proportional to energy. What does this mean? Well, that means that if our frequency is high, that means our wavelength will be small or low because inverse means that they're opposites of each other. Now, directly proportional means that if one is high the other one is high. So, if my frequency is high, my energies will be high. Conversely, if I say my frequency values are small or low, that means my wavelength values are high or large. And because frequency and energy are again directly proportional, if frequencies are low, energies would also be low. So, just remember this relationship between these three terms. Frequency and energy are directly related; they both go up or go down together. They are the opposite or inversely proportional to wavelength.

Which energy wave would have the highest frequency from the wavelengths provided?

• A. Wave A (453 nm)
• B. Wave B (707 nm)
• C. Wave C (325 nm)
• D. Wave D (910 nm)

Here’s what students ask on this topic:

What is the relationship between wavelength and frequency?

The relationship between wavelength (λ) and frequency (ν) is inversely proportional. This means that as the frequency of a wave increases, its wavelength decreases, and vice versa. Mathematically, this relationship is expressed by the equation:

$c=\lambda \nu$

where $c$ is the speed of light (approximately 3.00 × 10⁸ m/s). This inverse relationship is crucial for understanding how different types of electromagnetic radiation behave.

How do you calculate the energy of a photon?

The energy of a photon can be calculated using the equation:

$E=h\nu$

where $E$ is the energy of the photon, $h$ is Planck's constant (6.626 × 10^-34 J·s), and $\nu$ is the frequency of the photon. This equation shows that the energy of a photon is directly proportional to its frequency.

What units are used to measure wavelength and frequency?

Wavelength is typically measured in meters (m), although it can also be expressed in other units such as nanometers (nm) or angstroms (Å) depending on the context. Frequency is measured in Hertz (Hz), which is equivalent to one cycle per second (s^-1). These units help quantify the properties of electromagnetic waves.

What is the speed of light and how is it related to wavelength and frequency?

The speed of light in a vacuum is approximately 3.00 × 10⁸ meters per second (m/s). The speed of light (c) is related to wavelength (λ) and frequency (ν) by the equation:

$c=\lambda \nu$

This equation shows that the speed of light is the product of the wavelength and frequency of an electromagnetic wave. This relationship is fundamental to understanding how light and other forms of electromagnetic radiation propagate through space.

Why are frequency and energy directly proportional?

Frequency and energy are directly proportional because the energy of a photon is given by the equation:

$E=h\nu$

where $E$ is the energy, $h$ is Planck's constant, and $\nu$ is the frequency. Since Planck's constant is a fixed value, the energy of a photon increases as its frequency increases. This direct proportionality is essential for understanding phenomena like the photoelectric effect and the behavior of different types of electromagnetic radiation.