Which type of light has the longest wavelength

Q: Which of the following has the longest wavelength but?

Gamma rays < X-rays < Ultraviolet light < visible light < infrared < microwaves < radio waves. The order of the frequencies these waves is the reverse of the above order. Therefore, the radio waves have the longest wavelength amongst the EM waves, which range from millimetres to kilometres.

Q: Which of the following waves has the longest wavelength *?

Radio waves have the longest wavelength, and gamma rays have the shortest wavelength.

The electromagnetic spectrum is a range of wavelengths of electromagnetic radiation. From long to short wavelength, the EM spectrum includes radio waves, microwaves, infrared, visible light, ultraviolet, x-rays and gamma rays.

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Which has the longest wavelength?
Which of the following has the longest wavelength but?
Which of the following waves has the longest wavelength *?

Which row of the table correctly shows how the wavelengths of various types of electromagnetic waves compare with each other?

In this question, we’re given a table. Each row of the table gives five different types of electromagnetic waves in a certain order. We need to work out which row of the table gives these waves in the correct order: from longest wavelength in the far left-hand column to shortest wavelength in the far right column.

Before we try and answer this question, let’s remind ourselves about the electromagnetic spectrum. As the name suggests, the electromagnetic spectrum is just a spectrum of different types of electromagnetic waves. The different types of electromagnetic wave are defined by their wavelengths. At one end of the spectrum, we have electromagnetic waves with very long wavelengths. And at the other end of the spectrum, the waves have very short wavelengths.

To help us understand this, we can sketch a wave that has a long wavelength at one end and a short wavelength at the other end. Notice how the wavelength decreases smoothly. There are no sudden changes or jumps, just a nice continuous wave. Then, we can divide this into regions, where each range of wavelengths corresponds to a different type of electromagnetic wave. Keep in mind that this wave is just a way of showing whether wavelengths are shorter or longer. In reality, the differences in wavelengths for these wave types will occur over several orders of magnitude, unlike this visual aid we are using. So, let’s now label these regions.

Recall that radio waves have the longest wavelength of any electromagnetic wave. Next, it’s microwaves, then infrared, then visible light, which contains all the colors we can see, then we have ultraviolet, and then X-rays. Finally, the type of wave with the shortest wavelength is 𝛾. Now we know how the wavelengths of the different types of electromagnetic waves compare, we can go back to the table given to us and see which row is correct.

Let’s start with row i. This row tells us that radio waves have the longest wavelength and 𝛾 rays have the shortest, which we know is correct. However, let’s look at these types in between. This row suggests that X-rays have a longer wavelength than visible light and that visible light has a longer wavelength than infrared. This is not correct. These three types are not in the correct order. So, we know row i cannot be the correct answer.

Now let’s look at row ii. Out of the five types of wave in this row, we know radio waves must have the longest wavelength because they have the longest wavelength of any electromagnetic wave. However, this row suggests that radio waves have shorter wavelengths than visible light, ultraviolet light, and X-rays. This is definitely not correct. This is enough for us to rule out row ii.

Row iii suggests that infrared waves have the longest wavelength of these types. Although we know that radio waves and microwaves have longer wavelengths, they are not included anywhere in this row. So, it is correct to say that of these types, infrared has the longest wavelength. This row also suggests that 𝛾 rays have the shortest wavelength, which we know is true. And these other three types — visible, ultraviolet, and X-rays — are also in the correct order.

So, everything in row iii seems to be correct. Row iii could definitely be the correct answer to this question. But just to double check, let’s also think about the final two rows.

Row iv suggests that X-rays and 𝛾 rays have the two longest wavelengths. We know this isn’t true; these waves actually have the two shortest wavelengths. So, row iv is not the correct answer.

Row v correctly lists the order of radio waves, microwaves, and infrared. However, visible light and ultraviolet are in the wrong order. Visible light has a longer wavelength than ultraviolet. So, row v can be ruled out.

This leaves us with row iii. Row iii is the only row that lists five types of electromagnetic wave in the correct order, from longest wavelength to shortest. So, the row of the table that correctly compares the wavelengths of various electromagnetic waves is row iii.

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Our eyes are sensitive to light which lies in a very small region of the electromagnetic spectrum labeled "visible light". This "visible light" corresponds to a wavelength range of 400 - 700 nanometers (nm) and a color range of violet through red. The human eye is not capable of "seeing" radiation with wavelengths outside the visible spectrum. The visible colors from shortest to longest wavelength are: violet, blue, green, yellow, orange, and red. Ultraviolet radiation has a shorter wavelength than the visible violet light. Infrared radiation has a longer wavelength than visible red light. The white light is a mixture of the colors of the visible spectrum. Black is a total absence of light.

Earth's most important energy source is the Sun. Sunlight consists of the entire electromagnetic spectrum.

Learn more:

(Wavelength image from Universe by Freedman and Kaufmann.)The visible violet light has a wavelength of about 400 nm. Within the visible wavelength spectrum, violet and blue wavelengths are scattered more efficiently than other wavelengths. The sky looks blue, not violet, because our eyes are more sensitive to blue light (the sun also emits more energy as blue light than as violet).The visible indigo light has a wavelength of about 445 nm.The visible blue light has a wavelength of about 475 nm. Because the blue wavelengths are shorter in the visible spectrum, they are scattered more efficiently by the molecules in the atmosphere. This causes the sky to appear blue.

The visible green light has a wavelength of about 510 nm. Grass, for example, appears green because all of the colors in the visible part of the spectrum are absorbed into the leaves of the grass except green. Green is reflected, therefore grass appears green.

The visible yellow light has a wavelength of about 570 nm. Low-pressure sodium lamps, like those used in some parking lots, emit a yellow (wavelength 589 nm) light.

The visible orange light has a wavelength of about 590 nm.The visible red light has a wavelength of about 650 nm. At sunrise and sunset, red or orange colors are present because the wavelengths associated with these colors are less efficiently scattered by the atmosphere than the shorter wavelength colors (e.g., blue and purple). A large amount of blue and violet light has been removed as a result of scattering and the longwave colors, such as red and orange, are more readily seen.

There are many wavelengths in the electromagnetic spectrum the human eye cannot detect.

Energy with wavelengths too short for humans to see

Energy with wavelengths too short to see is "bluer than blue". Light with such short wavelengths is called "Ultraviolet" light.

How do we know this light exists? One way is that this kind of light causes sunburns. Our skin is sensitive to this kind of light. If we stay out in this light without sunblock protection, our skin absorbs this energy. After the energy is absorbed, it can make our skin change color ("tan") or it can break down the cells and cause other damage.

Energy with wavelengths too long for humans to see

Energy whose wavelength is too long to see is "redder than red". Light with such long wavelengths is called "Infrared" light. The term "Infra-" means "lower than".

How do we know this kind of light exists? One way is that we can feel energy with these wavelengths such as when we sit in front of a campfire or when we get close to a stove burner. Scientists like Samuel Pierpont Langley passed light through a prism and discovered that the infrared light the scientists could not see beyond red could make other things hot.

Very long wavelengths of infrared light radiate heat to outer space. This radiation is important to the Earth's energy budget. If this energy did not escape to space, the solar energy that the Earth absorbs would continue to heat the Earth.

Which has the longest wavelength?

Radio Waves -- The waves in the electromagnetic spectrum that have the longest wavelengths and lowest frequency are called radio waves.

Which of the following has the longest wavelength but?

Gamma rays < X-rays < Ultraviolet light < visible light < infrared < microwaves < radio waves. The order of the frequencies these waves is the reverse of the above order. Therefore, the radio waves have the longest wavelength amongst the EM waves, which range from millimetres to kilometres.