Electromagnetic Spectrum (Simplified): Videos & Practice Problems

The electromagnetic spectrum encompasses all wavelengths and frequencies of electromagnetic radiation, from long radio waves to gamma rays. As one moves from left to right, wavelengths decrease while frequency and energy increase. The visible light spectrum, a small segment of this continuum, includes colors represented by ROYGBIV (red, orange, yellow, green, blue, indigo, violet), ranging from 700 nm (red) to 380 nm (violet). Understanding this spectrum is crucial for grasping concepts in physics and chemistry, including energy transfer and light behavior.

Electromagnetic Spectrum (Simplified) Concept 1

Hey everyone. So in this video, we're going to talk about the electromagnetic spectrum. Now, the electromagnetic spectrum itself is just a continuum of electromagnetic radiation that contains all wavelengths and frequencies. Electromagnetic radiation is just the flow of light energy that is traveling at the speed of light through space as either an electric or magnetic field. It was the physicists Max Planck and Albert Einstein who theorized that this radiation was made of packets or particles. This light particle or packet was referred to as a photon and a group of them was called a quantum. As we move through the electromagnetic spectrum, as we go from left to right, we're going to be going from the radio waves all the way to gamma rays. What we need to realize here is that moving in this direction has a profound effect on our wavelength, our frequency, and also energy. So, as you're moving from left to right towards gamma rays, our wavelengths will be decreasing and our frequencies will be increasing. Remember, we talked about this in previous videos, that there is a direct relationship between frequency and energy. So here, if my frequencies are increasing, that means my energies are also increasing.

If we take a look at the electromagnetic spectrum itself, up here we have μ, which represents Hertz, which represents our frequency. And we're going to start out with our long radio waves. They have energies that are around 10⁰ Hertz or 1 Hertz, and they can go up further as we move from left to right. On the bottom, we have λ as our symbol, which represents wavelength, traditionally in meters. So if we're taking a look here, we can see that our frequency here is 1 Hertz and our wavelength is 10⁸ meters. You can see the wavelength is pretty huge. It's a large number; frequency is a very small number. And we're going to start out with our long radio waves to start. When we go past the long radio waves, we're going to go into our radio waves. And remember, radio waves themselves are broken up into AM and FM. If you're looking at the dial on your car for the radio, you know that you can transition from AM stations to FM stations. And remember that AM stations typically have smaller numbers, because they have smaller frequencies. FM have larger numbers usually in terms of megahertz, and that's why they're higher up. Once we pass radio waves, we go into microwave, and then after microwave, we go into infrared. Now, this portion here that's very colorful, remember, this is the portion of the electromagnetic spectrum that we can see with our own eyes without the use of instruments. This is the visible light region. So, you can see that the visible light region makes up a very small portion of the entire electromagnetic spectrum.

After the visible light spectrum, we go into UV, and after UV, we have X-rays and then finally gamma rays. Some books may talk about cosmic rays out in space, but we typically don't talk about this within chemistry, so just realize that we're just going to go to gamma rays. What can we see here? Well, this wave here represents the relationship of wavelength and frequency. We can see that initially, the distance between each wave is pretty big, there's a vast distance between them. Remember that distance represents our wavelength. You can see the wavelength starts off pretty high. And what happens as we move from left to right? You can see the wavelength is becoming more tightly packed. That's because my wavelength, the distance between crests of the waves, is decreasing, and the frequency of waves I get per amount of time is increasing, so my frequency is increasing. But you might say, Jules, there are so many different terms here with the electromagnetic spectrum. How am I supposed to remember all of them? Well, that's when we use our memory tool. So our memory tool here says that large rude Martians invented very unusual X-ray guns. So, if we take a look here at everything we highlighted, we can say large stands for long radio waves, rude stands for radio waves, Martians are microwaves, invented is for infrared, very is for our visible light spectrum, the small portion here, Unusual is for UV, X-ray is for X-rays. And then guns here are for gamma rays. So, use this memory tool to help you remember the order of the electromagnetic spectrum. And remember, as we move from long radio waves all the way to gamma rays, we see that our wavelengths are decreasing as our frequency is increasing.

Electromagnetic Spectrum (Simplified) Example 1

So here we're going to use our memory tool to help us with this example question. It says, which kind of electromagnetic radiation contains the greatest amount of energy per atom? Here, remember, as we move from left to right, we're going to say that our frequency increases. So μ is increasing. And this is important to know because remember, energy and frequency are directly related. So the greatest amount of energy would correlate to the highest frequency. So who's most to the right here? If we look, microwave is for Martians so that's out. X-ray is over here, and the only thing higher than that is gamma rays, and we don't have gamma rays listed as an option. So here, our answer would have to be choice b. Remember, large rude Martians invented very unusual x-ray guns, stands for long radio waves. Radio waves, here we have microwaves, here we have infrared, the visible light spectrum, we have UV light, x-ray and then gamma ray.

Electromagnetic Spectrum (Simplified) Concept 2

So the visible light spectrum represents a small portion of the continuum, the electromagnetic spectrum itself, that can be seen without the aid of instruments by us. And here we're going to say that in order to remember the colors involved with the visible light spectrum, just remember ROY G BIV. Here, R is red, then we have orange, yellow. We have here green, blue, indigo, and violet. Now realize that sometimes in more modern visible light spectrums, they'll combine indigo and violet together and just say it's violet. And when we're talking about the visible light spectrum, realize that it ranges from 700 nanometers for red light all the way to around 380 nanometers for violet light. And remember, in terms of the electromagnetic spectrum, we're going to say that red is near infrared and then the violet end is next to ultraviolet. Now that's blue, but you get what I mean. So that's a good way of remembering what other electromagnetic radiations are near the visible light spectrum. Red is next to the infrared and then violet is next to the ultraviolet. So just remember, the visible light spectrum is important to us because that's what we can see with our bare eyes without the use of any types of instruments.

Which of the following sources of electromagnetic radiation will have the highest energy?

• A. Light A (595 nm)
• B. Light B (0.0303 cm)
• C. Light C (0.000510 m)
• D. Light D (291 μm)

Answer: (A)

A carbon–oxygen double bond within a sugar molecule absorbs electromagnetic radiation at a frequency of 6.0 x 10¹² s^-1. What portion of the electromagnetic spectrum does this represent?

• A. Radio Waves
• B. Micowave
• C. Infrared
• D. Green Light
• E. Gamma Ray

Answer: (C)

X-Ray detectors are devices that use scintillators to convert X-rays into light in order to detect X-Rays indirectly. Which of the following would be picked up by an X-Ray detector:radiation with a wavelength of 0.85 nm or a frequency of 6.52 x 10¹¹ s^-1?

• A. radiation with a wavelength of 0.85 nm
• B. radiation with a frequency of 6.52 x 10¹¹ s^-1

Answer: (A)

Here’s what students ask on this topic:

What is the electromagnetic spectrum and why is it important?

The electromagnetic spectrum is a continuum of all electromagnetic radiation, encompassing all wavelengths and frequencies. It ranges from long radio waves to gamma rays. As you move from left to right on the spectrum, wavelengths decrease while frequency and energy increase. This spectrum is crucial for understanding various concepts in physics and chemistry, such as energy transfer and light behavior. It also includes the visible light spectrum, which is the portion of the spectrum that can be seen with the naked eye, represented by the colors ROYGBIV (red, orange, yellow, green, blue, indigo, violet).

How do wavelength and frequency relate to each other in the electromagnetic spectrum?

In the electromagnetic spectrum, wavelength and frequency have an inverse relationship. As you move from left to right on the spectrum, wavelengths decrease while frequencies increase. This means that longer wavelengths correspond to lower frequencies, and shorter wavelengths correspond to higher frequencies. This relationship is crucial for understanding the behavior of different types of electromagnetic radiation, such as radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays.

What is the visible light spectrum and how is it represented?

The visible light spectrum is a small portion of the electromagnetic spectrum that can be seen with the naked eye without the aid of instruments. It includes the colors red, orange, yellow, green, blue, indigo, and violet, often remembered by the acronym ROYGBIV. The visible light spectrum ranges from approximately 700 nanometers (red) to 380 nanometers (violet). Red light is near the infrared region, while violet light is near the ultraviolet region. This spectrum is important because it represents the range of light that humans can perceive.

What are the different types of electromagnetic radiation in the spectrum?

The electromagnetic spectrum includes various types of electromagnetic radiation, each with different wavelengths and frequencies. From longest to shortest wavelength, these types are: long radio waves, radio waves (AM and FM), microwaves, infrared, visible light, ultraviolet (UV), X-rays, and gamma rays. Each type of radiation has unique properties and applications, such as communication (radio waves), cooking (microwaves), and medical imaging (X-rays).

How can you remember the order of the electromagnetic spectrum?

A useful mnemonic to remember the order of the electromagnetic spectrum is: 'Large Rude Martians Invented Very Unusual X-ray Guns.' This stands for Long radio waves, Radio waves, Microwaves, Infrared, Visible light, Ultraviolet, X-rays, and Gamma rays. This mnemonic helps recall the sequence from longest to shortest wavelength, making it easier to understand the spectrum's structure and the relationship between different types of electromagnetic radiation.