Photons

[5614]

i know there is another thread going called 'photons' as well, but i wanted to change the subject a bit, so started a new one....

 

basically, i know what a photon is, and i understand everything that has been said in the other thread [photons] but what i wanna know is just all the basics, what i need is to just sit down and read an essay on photons, starting at the basics [not what it is, but how it made/interact] and then get into more details after......

 

so does someone know a website, or just know about photons themselves, start with the basics, ill read it, then, [or another time, if u dont have loads of time to waste typing stuff!] get into more details

 

thanks!

[pulkit]

I'll give you a brief historical build up leading to photons :

 

Upto the end of the 19th century (nearly) every phycist thought of light ot be a wave.

However it was about that time that people like Hertz came up with certain interesting experiments that involved phenomena of light which cannot be explained with the wave nature proposed at that time. The most famous of these is the photoelectric effect (look that experiment up on google, it is very famous). So, to explain photoelectric effect none other than Mr.Albert Einstein came up with an equation which you can derive only if you assume light to consist of a continous stream of small particls called photons.

 

The basic difference in the two approaches can be understood if you imagine light hitting a surface :

1) A wave would lead to a continous influx of energy on to that surface.

2) A particle nature (photons) would mean energy comes in a continous stream of small packets.

Though this seems quite irrelevant to a novice, but it is an extremely important concept and the essence of all modern theory on light.

 

By the way, it was acctually a gentleman by the name of Max Planck who had come up with this idea of energy being in the form of small packets in radiation around the year 1900.

 

Another way to look at it is to think of energy as you think of water, you see a photon picture merely means that the water itself is made of small "discrete" units (molecules), but still appears as a continous stream because of the shear number of molecules involved, exact same is the approach to photons.

 

Finally, light is now though to possess a dual nature which is necessary because some phenomena can only be explained if we think of it as a wave and others only if it were a particle. So depending on the situation, you have a choice wether to understand light's behaviour as particle or as wave.

 

THeres this famed noble prize acceptance speech (around the early years of the 20th century) of a physicist (i can't recollect who) who said something like

On Mondays, Tuesdays and Wednesdays we think of light as waves

On Thursdays, Fridays and Saturdays we think of it as a particle

And on Sundays we simply pray.

[Nirav]

i know there is another thread going called 'photons' as well' date=' but i wanted to change the subject a bit, so started a new one....

 

basically, i know what a photon is, and i understand everything that has been said in the other thread [photons'] but what i wanna know is just all the basics, what i need is to just sit down and read an essay on photons, starting at the basics [not what it is, but how it made/interact] and then get into more details after......

 

so does someone know a website, or just know about photons themselves, start with the basics, ill read it, then, [or another time, if u dont have loads of time to waste typing stuff!] get into more details

 

thanks!

 

 

c my friend... actually photons can be considered as a field (containing both magnetic and electric components) whose intial fluctation level is zero. but according to relativity theory, nothing can be considered to b at absolute rest.

hence we can consider these fields as waves.

in this way the phoyons interact with other things by its wave property.

 

HOPE IT WASNT BIG!

Glad.