That's hard to discuss, because the electromagnetic spectrum has no ends.
If you name a frequency, then no matter how low it is, I can name a lower one,
and no matter how high it is, I can name a higher one. So, it's easy to describe
the size of the visible portion, but it's hard to describe the size of the full EM spectrum.
So let's just talk about the size of the part of the E&M spectrum that humans
use for radio communication, and ignore all the rest of it ... the infra-red, x-rays,
ultraviolet, gamma rays, all that other stuff. Only the part that we know how to
generate and modulate with very precise frequency control, and transmit and
receive over significant distances.
That's the portion of the E&M spectrum with frequencies from about 60 KHz
to about 100 GHz (wavelengths from about 3 millimeters to 5 kilometers).
'Linearly', that's a range of about 100 GHz bottom-to-top. But a much better
way to talk about parts of the E&M spectrum is logarithmically ... how many
'octaves' (doublings) or 'decades' (multiplied by 10) they cover.
Measured that way, our use of radio spans about 21 octaves, or about 6.2 decades.
Now we're ready to go look up the frequency/wavelength range of visible light.
A typical human eye will respond to wavelengths from about 390 to 750 nm
(3.9 to 7.5 x 10-4 millimeters). In terms of frequency, this corresponds to a band
in the vicinity of 400-770 THz (400,000 to 770,000 GHz).
That makes the visible range about 0.95 octave, or about 0.28 decade ... only
about 41/2% as wide as the range of wavelengths we use for radio communication!
Now, for fun, we'll try and include those other E&M phenomena that we've been ignoring.
We'll still have to decide where the ends of the spectrum are, because it really doesn't
have any.
For the bottom frequency, let's take 60 Hz. That's the small amount of RF that
radiates from power lines, which we always ignore. The wavelength is about
5,000 kilometers. (!)
Let's take gamma radiation for the top end ... the stuff generated in nuclear
decay, supernovas, black holes, that sort of thing. Dangerous stuff because
of its high energy. We're still here only because Earth's atmosphere absorbs
most of the gamma radiation from space, and not much of it ever reaches the
ground. Astronauts have to be shielded from it.
Gamma rays typically have frequencies above 10 exahertz (or >1019 Hz), and
wavelength less than 10 picometers (less than the diameter of an atom.)
So now, our 'expanded' range of electromagnetic spectrum covers 57.2 octaves,
or 17.2 decades, and the range of visible light is about 1.6% as wide as that.
Bottom line . . . we don't actually "see" a whole lot of the E&M spectrum, but
we know how to build instruments that detect the parts we can't see.
That it is a part of the electromagnetic spectrum
Electromagnetism is manifest along a continuum between slower radio waves and faster energy gamma waves. Visible light can be found in the range between infrared light (slower than waves of visible light) and ultraviolet light (faster than waves of visible light).
Lightis an electromagnetic radiation that is visible to the human eye, and is responsible for the sense of sight.
All types of lens that see parts of the electromagnetic spectrum other than light. E.g. infrared cameras
Yes, more or less. James Clerk Maxwell predicted that an electromagnetic wave would propagate at the speed of light. Therefore, he also suspected that light was an electromagnetic wave. This was confirmed later.Yes, more or less. James Clerk Maxwell predicted that an electromagnetic wave would propagate at the speed of light. Therefore, he also suspected that light was an electromagnetic wave. This was confirmed later.Yes, more or less. James Clerk Maxwell predicted that an electromagnetic wave would propagate at the speed of light. Therefore, he also suspected that light was an electromagnetic wave. This was confirmed later.Yes, more or less. James Clerk Maxwell predicted that an electromagnetic wave would propagate at the speed of light. Therefore, he also suspected that light was an electromagnetic wave. This was confirmed later.
Visible light is a small section in the electromagnetic spectrum.
Yes. visible light is in the electromagnetic spectrum.
Visible light is a small section in the electromagnetic spectrum.
Most of the electromagnetic spectrum is not visible.
Most of the electromagnetic spectrum is not visible.
the range of the spectrum that's known as "visible light"
Visible light falls between the wavelengths of 380 nm and 760 nm in the electromagnetic spectrum.
The visible portion of electromagnetic spectrum is called the visible light and is the electromagnetic wave with the wavelength between 380 - 740 nm.
Most of the electromagnetic spectrum is not visible.
in electromagnetic spectrum visible light is safe for humans
the light spectrum
The visible spectrum is the portion of the electromagnetic spectrum that is visible to (can be detected by) the human eye. Electromagnetic radiation in this range of wavelengths is called visible light or simply light.