What percentage is visible light on the electromagnetic spectrum?

Answer 1

Good question-- See the link. Roughly the visible region is 300 nm to 650. so that's 350 nm total. The electromagnetic spectrum goes from 10 Megameters to 1 picometer. So the percentage of the spectrum occupied by visible light is tiny, just 3.5 X 10-9 divided by 10^19 ---- So that's 3.5x10-26 %. So many zeros....! Yikes. Gamma rays (picometers) (10-12)

Hard X-rays

Soft X-Rays

Extreme ultraviolet

Near ultraviolet

Visible light

Near infrared

Moderate infrared

Far infrared

Extremely high frequency (Microwaves)

Super high frequency (Microwaves)

Ultra high frequency (Radio)

Very high frequency (Radio)

High frequency (Radio)

Medium frequency (Radio)

Low frequency (Radio)

Very low frequency (Radio)

Voice frequency (Radio)

Extremely low frequency (Radio) 10 Megameters (10 X 106) Actually the electromagnetic spectrum goes off as far as you want in both directions - there are electromagnetic waves with wavelengths as small as you want, and others as large as you want. So really the answer is 0%. If you meant to ask what percentage of the electromagnetic energy from the sun is visible (for instance) then the answer is nonzero, but I don't know what it is. If you meant to ask a question of the kind that has been answered above (what percentage of the spectrum from 10 megameters to 1 picometer is visible) then the question is not well defined: the answer depends not just on the bounds but on what scale you use. I think the answer above is mistaken. If you go by wavelength, my answer (to that question) would be: 3.5x10-7 divided by 107, which is 3.5x10-14 or 3.5x10-12%. If you use frequency instead of wavelength: The bounds on wavelength given above correspond to 30 Hz to 3x1020Hz, with visible light between 4.6x1014Hz and 1015Hz. Then, the answer would be 5.4x1014 divided by 3x1020, which is 1.8x10-6, or 0.00018%. If you want to use a logarithmic scale, which is more sensible in some ways, then the answer is much higher. I don't know exactly because I don't have a calculator with logarithms here, but it's around 1.5%.

Answer 2

Visible light makes up approximately 0.0035% of the electromagnetic spectrum. It has wavelengths ranging from about 400 to 700 nanometers, representing the portion of the spectrum that our eyes can detect.

Answer 3

Since the electromagnetic spectrum runs from near infinite wavelength to infinitesimal wavelength, the visible light spectrum is 0% of that: any finite number divided by infinity is zero.

Answer 4

The human eye can only detect visible light which constitutes less than one millionth of one percent of the entire electromagnetic spectrum. So next time you're tempted to believe only what you can see, think again.

Answer 5

In order to answer that, we'd need to know the ends of the EM spectrum,

but it doesn't have any !

Just to get a number for you, I'll make up some ends for the spectrum:

---- One end: The NIST 'atomic clock' signal. 60 KHz ===> 5000 meters.

---- Other end: Lowest frequency of gamma rays. 1019 Hz ===> 3 x 10-11 Meters

---- That makes the length of the EM spectrum (1019 - 60,000) Hz, or a factor of 1.67 x 1014 .

Now I'll make up some numbers for the limits of visible light:

---- Red end: 400 x 1012 Hz ===> 750 nanometers

---- Violet end: 800 x 1012 Hz ===> 375 nanometers

---- That makes the length of the visible spectrum 4 x 1014 Hz, and a factor of 2.

Now that we know the ends and length of both ranges, we can compare them.

---- In raw frequency, visible range/total EM = 4 x 1014/1019 = about 0.003 percent.

---- In logarithmic terms, log(visible bandwidth)/log(total EM bandwidth) = log(2)/log(1.67 x 1014) = about 2.12 percent.

Answer 6

Executive Summary / Short Answer:

Less than 0.004 percent of the Hertz in the spectrum,

or about 2.1 percent of the octaves in the spectrum. To see where these numbers come from, read below:

==================================

Before anyone can answer that, we have to agree on the limits of the electromagnetic

spectrum, because it actually has no beginning or end.

-- Let's say the spectrum begins at the bottom of the AM radio dial ... 550 KHz.

-- And let's say it ends at the lowest-frequency gamma rays ... 1019 Hz.

Now, there are a few different ways to describe that range. We could say that it's ...

-- (1019 - 550 x 103) = (almost exactly the same as 1019) Hertz, or

-- 1019/550 x 103 = a ratio of 1.818 x 1013between the top and bottom frequencies,

of the spectrum, or

-- log(that ratio)/log(2) = 44 octaves of frequency.

Using the first description:

Between 400 nm (violet) an 750 nm (red), visible light spans the frequency range

of roughly (7.4948 to 3.9972) x 1014 = 3.4976 x 1014 Hertz.

Out of the 1019 Hertz in the full spectrum, that amounts to about 0.0035% of them.

Using the second description:

From the bottom of the spectrum to the top . .. multiply by 1.8181 x 1013 .

From the bottom of the spectrum to the bottom of visible: multiply by 7.27 x 108

From the bottom of the spectrum to the top of visible: multiply by 1.36 x 109

(Not too impressive, but I don't know how else to compare them, in this format.)

Using the third description: (my favorite way to look at it)

Number of octaves covered by the electromagnetic spectrum: 44

Number of octaves covered by visible light: 0.9 of one

That's about 2.1% of the octaves of frequency in the spectrum.

Answer 7

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Answer 8

less than 1/1,000,000 of a percent

Answer 9

as much as you want to see!