Question

electromagnetic wave which can penetrate most of the solid is affect by size? or something else?

Answer 1

As you may know, electromagnetic radiation can be though of as either a wave or a particle.

We call the particle form photons. If \[ \nu \] is the frequency of the wave form, it turns out the energy of particle form, the photons is proportional to \( \nu \).

In other words, higher frequency -> higher energy.

The higher the energy of a photon, the greater ability it has to penetrate matter.

Visible light has frequencies ν between 400 and \( 800 \times 10^{12} \ Hz \). If you hold stand in front of a visible light source, like the sun, the light doesn't penetrate you. That's why you have a shadow.

X-rays on the other hand have a frequency around \( 10^{18} \) Hz; that means the photons of X-rays have around 10,000 to 100,000 times more energy that the photons of visible light. They can penetrate the soft-tissue of your body but are absorbed by bones. This is how we may X-rays of people.

Gamma rays, at the far end of the electromagnetic spectrum have a frequency \( \nu \) of \(10^{20} \) Hz. That means the photons of gamma radiation have around 10,000,000+ times more energy than visible light. Gamma radiation is therefore very dangerous to humans, because it hard to shield us from it and it can easily penetrate our bodies.

At the other end of spectrum, we have radio waves, with frequencies around \( 10^4 = 1000 \) Hz. You might have noticed when you're underground in a tunnel, your radio stops working. This is because the radio waves have been absorbed by the matter above you.

Answer 2

You might find this helpful:
http://en.wikipedia.org/wiki/File:EM_Spectrum_Properties_edit.svg

Answer 3

'electromagnetic radiation can be though of as either a wave or a particle. ' , does that mean only energy type electromagnetic wave can penetrate while particle type can't? Does the wave length affect the penetration power?

Answer 4

No, the fact is electromagnetic radiation sometimes behaves like a wave and sometimes like a particle. It's the same radiation; just that its properties are sometimes more wave-like and sometimes more particle-like.

Wave length is intimately related to frequency:
(Wave length) x (frequency) = speed of wave.

In symbols, if \( \lambda \) is the wave length,
\[ \lambda . \nu = c \]
where c is the speed of light.

Thus, the higher the frequency, the lower the wave length; the higher the wave length, the lower the frequency.

In terms of the analysis above:
Higher frequency -> higher energy

Hence
Longer wave length -> higher frequency -> higher energy
Shorter wave length -> lower frequency -> lower energy

Answer 5

ok i will note those down ^^

Answer 6

that was a really helpful for me . but i need , just definition of , X ray , uv light, infrared , microwave , and radio frequency.

Answer 7

Have a look at this diagram:

http://en.wikipedia.org/wiki/File:EM_Spectrum_Properties_edit.svg

Answer 8

yes , i already seen ,,
but i need only defination of that , ?

Answer 9

For example:
DEFINITION An x-ray is an instance of electromagnetic (EM) radiation where the wave length of the radiation is between 0.01 and 10 nanometers.

We give names to the different parts of the EM spectrum; the cut-offs between the different types is somewhat arbitrary, with the exception of the visible spectrum, which is a function of our biology.

Answer 10

yeah , i think that enough , for defination , bundle of thanks sir ,