PDA

View Full Version : Wavelenght, frequencies


JPC
Jun15-07, 07:03 AM
hey how come the IR heat up materials more than UV ?
and why people say IR go longer distances

the way i see it :

UV have faster frequencies, they should have more energy
while IR have slower frequencies, should have less energy

or is it that when hitting a electron , photons that vibrate faster transfer less energy to the electron ?

---

and as for the distance , i thought photons would carry on forever
so is it that high frenquence photons loose their energy faster ?

---
and do photons see their frequencies slower as they get in contact with matter ?

russ_watters
Jun15-07, 07:54 AM
hey how come the IR heat up materials more than UV ? It doesn't, unless there is a difference in how certain materials aborb different wavelengths. and why people say IR go longer distances It doesn't. the way i see it :

UV have faster frequencies, they should have more energy
while IR have slower frequencies, should have less energy Not faster or slower, higher and lower, but yes. or is it that when hitting a electron , photons that vibrate faster transfer less energy to the electron ?
Essentially yes.
and as for the distance , i thought photons would carry on forever
so is it that high frenquence photons loose their energy faster ? They will carry on forever if they don't hit anything. and do photons see their frequencies slower as they get in contact with matter ? That one I'm not sure about - there may be an effect like that in refraction.

ice109
Jun15-07, 08:29 AM
That one I'm not sure about - there may be an effect like that in refraction.

i don't think the frequency changes, the wavelength and the velocity do though