Unaffected by EM waves!

[Guest GinoEdgar]

Although i like to think i understand electromagnetic waves there is still something i don't understand:

Why in the case of light waves do some substances not reflect any light out at all (such as glass), i know its because it doesn't 'absorb' the frequencies and therefor photons aren't released, but what is it exactly which causes it to be unaffected by the electromagnetic wave?

 

In the same sense why doesn't all the radio waves and other waves shooting around us drastically effect our body?

[swansont]

Glass does reflect light. I've had spectroscopy layouts that relied on the 4% reflection you get with normal incidence. The amount of reflection you get depends on the index of refraction. (Unless you do a trick with antireflection coatings, which rely on destructive interference from multiple reflection surfaces)

[mississippichem]

Although i like to think i understand electromagnetic waves there is still something i don't understand:

Why in the case of light waves do some substances not reflect any light out at all (such as glass), i know its because it doesn't 'absorb' the frequencies and therefor photons aren't released, but what is it exactly which causes it to be unaffected by the electromagnetic wave?

 

Be careful not to mix up a phenomenon like reflection with others like absorption and emission (things like fluorescence and phosphorescence).

 

In the same sense why doesn't all the radio waves and other waves shooting around us drastically effect our body?

 

Radio waves are very low energy compared to things like UV or even visible light. They are only energetic enough to move electrons around in metals or cause molecules to vibrate a little faster. It takes much higher energy, generally speaking, to cause much chemistry to happen directly; including your physiological chemistry.

[lemur]

Although i like to think i understand electromagnetic waves there is still something i don't understand:

Why in the case of light waves do some substances not reflect any light out at all (such as glass), i know its because it doesn't 'absorb' the frequencies and therefor photons aren't released, but what is it exactly which causes it to be unaffected by the electromagnetic wave?

 

In the same sense why doesn't all the radio waves and other waves shooting around us drastically effect our body?

Try this link: http://en.allexperts.com/q/Physics-1358/2009/12/Transparent-materials.htm. It basically explains that glass doesn't reflect because it has no free electrons, and it doesn't scatter light because it's uniform in texture. I forget why it says it doesn't absorb, but it covered that too.

[swansont]

Try this link: http://en.allexperts.com/q/Physics-1358/2009/12/Transparent-materials.htm. It basically explains that glass doesn't reflect because it has no free electrons, and it doesn't scatter light because it's uniform in texture. I forget why it says it doesn't absorb, but it covered that too.

 

Any explanation that says uncoated glass doesn't reflect (other than at Brewster's angle) is wrong.

 

http://physics-animations.com/Physics/English/rays_txt.htm

[lemur]

Any explanation that says uncoated glass doesn't reflect (other than at Brewster's angle) is wrong.

 

http://physics-anima...sh/rays_txt.htm

I don't think the article was intended to be that specific. I think it was just giving a general explanation for why light passes through glass but reflects off metal. Obviously glass creates a glare in many situations.