It is referred to as "electromagnetism" since electricity and also magnetism are linked:

A changing electric field produces a magnetic field,a changing magnetic ar produces one electric field,
... Around and also around ... !

So electricity and magnetism are connected in an continuous dance.

You are watching: What is the frequency of an electromagnetic wave that has a wavelength of 300,000 km?

This result heads off through room at the fastest rate possible: the speed oflight.

Here is the complete electromagnetic spectrum:

Higher frequency (rate that vibration) has more energy and shorter wavelength.

The spectrum is consistent with no sudden alters or boundaries.

But exactly how waves interact with matter depends on their energy and also the type of matter

Example: our Bodies

radio waves pass through our bodiessome microwaves get soaked up and heat us upskin absorbs part infrared and also light, and reflects the rest
UV (ultraviolet) is absorbed by the an extremely outer great of our skin (which reasons sunburn and also skin cancer)X-rays are soaked up at different rates by bone and also muscle so we deserve to see inside us
Gamma rays greatly pass through, but any kind of that get took in may damage our cell by ionization (see below)

So part waves pass right through ours bodies, others get reflected or soaked up at different rates.


Example: indigenous The Sun

A the majority of the the radiation from the sun gets reflected or absorbed by the atmosphere.


radiosome infraredvisible light, andsome ultraviolet

get every the way through:


Imagine: if our eyes could only check out X-rays the sky would it is in black!

So telescopes choose the NuSTAR X-ray telescope have to be in orbit.


We like to think that the spectrum as having actually these ranges:

There is disagreement on the exact selection values (for instance X-Rays native an X-ray tube and also Gamma rays native radioactive products overlap) yet here is a comfortable guide:

Typical WavelengthCommonly characterized Range
Radiometers (m)Above 10 cm
Microwavecentimeters (cm)1 mm to 10 cm
Infraredmicrometers (μm)750 nmto 1 mm
Light100s that nanometers 380 nm come 750 nm
UV100 nanometers 10 nm come 380 nm
X-raysnanometers (nm) 10 afternoon to 10 nm
Gamma rays picometers (pm)below 10 pm

See units in Equations for an ext about nanometers, picometers, etc.

Speed that Light

Electromagnetic waves take trip at the "Speed that Light" at almost 300,000,000 meters per second (to be exact: 299,792,458meters every second) in a vacuum.

That is 300 million meters every second, or:

3 × 108 m/s300,000 km/s186,000 miles every second

But the speed deserve to be slower ...

MediumSpeedmillion m/s
Olive oil204

At slow speeds the wavelength is shorter because that the same frequency.

We have the right to work out the wavelength:

wavelength = speedfrequency

Example: Red irradiate at a frequency that 4 × 1014

Ina vacuum the wavelength is:

3 × 1084 × 1014 = 7.5 × 10-7 = 750 nm

In water the wavelength is:

2.25 × 1084 × 1014 = 5.625 × 10-7 = 562 nm

The wavelength is different yet the light remains the exact same color as the frequency is the same.

Important: the wavelengths discussed on this web page are for a vacuum. Readjust them like above if not.

Wavelengths vs Frequency Activity

Try this:Walk across the room in 5 seconds:

taking long steps("longwavelength")and again taking brief steps("shortwavelength")

What is the frequency the your procedures in every case?

Now try that again yet take 20 seconds to cross the room. What happens?


A higher frequency (rate the vibration) has much shorter wavelengthand an ext energy.

Example: i beg your pardon has more energy, irradiate or X-rays?

X-rays have an ext energy, through frequencies approximately 1018, compared to light about 1014

Example: i beg your pardon has much more energy, red light or blue light?

Blue light has higher frequency (with much shorter wavelengths), so has more power than red.



Energy and Ionization

Gamma rays, x-rays, and also some ultraviolet waves have such high energy that they space "ionizing," an interpretation they can knock electrons out of atoms.

This provides atoms fee and an ext likely to form new chemistry reactions, which have the right to be harmful come our cells, death them or changing themso they flourish out of regulate and kind cancer.


How to remember the spectrum?

It goes: Radio, Micro, Infrared, Light, Ultraviolet, Rays

Radio and Microwaves room at the low power endInfrared is "before red"Visible light goes "Roy G Bv": Red Orange Yellow Green Blue VioletUltraviolet is "afterviolet"Rays (X-rays and also gamma rays) at the high energy end

To mental the energy and danger levels, think "Radio is low, yet rays are favor razors".

As Photons

Electromagnetic radiation behaves as waves, but likewise behaves together packets of energy called Photons.

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We deserve to measure a photon"s position and also momentum.Photons have actually no mass, however each photon has actually a certain amount of energy that counts on that is frequency (number that vibrations per second).Each photon has actually a wavelength

So the is favor a particle and likewise like a wave. This is called the "wave–particle duality".


Einstein wroteabout it:

"It seems as despite we must use sometimes the one theory and also sometimes the other, while at times we may use either."