Electrons-----Phtons~~need help plz!!! (1 Viewer)

[linxicm]

1)I do not know why the quantum theory can explain the UV catastrophe and

2)how does the heated black body vibrate electrons and then produce electronmagnetic wave now we know it is expressed as Phtons. It sounds like electrons produce phtons. I know it is a stupid question,but can u plz explain where do photons come from?

3) why the higher frequences like UV ,the lower intensity ? and what has lower intensity? electrons? current or photon?

4) in Phtoelectic effect, photos give energy to electrons to remove them from surface? but where do phtons afterwards? disappears or remaining in the object?

plz help me,plz! i am crazy now.......

Thanks so much......

 

[richz]

From hsc.csu

1. It was thought that the energy absorbed and emitted by a black body should be continuous, that is, could occur in any amount, and should increase as the wavelength became shorter. This was not supported by the experimental data as shown in the sketch. The amount of energy radiated reaches a maximum at a wavelength that depends on the temperature of the black body.

2. Photons are packets of energy, which is wat black bodies radiate and absorb.

3. dunno wat u are saying. But just remember higher frequency means a photon has more energy shown by eqn e=hf. Higher intensity means more photons and converse.

3. The photoelectric effect is when light is shone on an object and a electron is emitted. The electron is like the spark. In hertz'z exp the spark is made of electrons. But im not sure where the electron goes. But in solar cells electrons are collected in grid and this is transfered to the p type semiconductor to create a current.

hope it helps

 

[KFunk]

3) why the higher frequences like UV ,the lower intensity ? and what has lower intensity? electrons? current or photon?

4) in Phtoelectic effect, photos give energy to electrons to remove them from surface? but where do phtons afterwards? disappears or remaining in the object?

plz help me,plz! i am crazy now.......

Thanks so much......

3) According to planck the energy packed in each quantum (photon) is E = hf where h is planck's constant and f is the frequency of the photon. This means that the higher the frequency, the greater the energy i.e UV light has more energy than red light and gamma rays have more energy than x-rays.

You ask about intensity a bit but intensity actually isn't a property possessed by photons themselves. Intensity refers to the amount of photons released by an emitter per unit area or the amount recieved by a receiver per unit area.

I'm fairly sure that the proportionality between energy (E) and frequency (f) is an observational conclusion, I've never seen a completely satisfactory explanation of this myself so perhaps some of the uni students could shed light (excuse the pun) on this?

4) Photons are packets of energy and electrons within a certain material require a particular amount of energy in order to escape that material. If an electron impacts with a photon with the amount of energy (or greater) that it requires to escape then the energy packet that once was a photon gets transfered to the electron in the form of kinetic energy allowing the electron to escape from the material - so the photon no longer exists, its energy has been completely transfered to the electron.

EDIT: Refering back to light intensity, if you were to increase the intensity of the light shone on a surface you would not be giving electrons more energy (since you are creating more photons rather than photons with more energy. photons are discrete and the effects of photons on an electron are not added up) but you would cause more electrons to escape since there are more photons to collide with.

 

[linxicm]

i undertand it a lot more. Thanks you!