- #1

Rishabh Narula

- 61

- 5

of blackckbody radiation phenomena?

in particular the intensity versus

wavelength curve?

"A Blackbody consists of oscillators of

molecular dimensions.

Intensity is proportional to number of oscillators

with sufficient energy hv

emitting radiation,

and that number of oscillators

is proportional to e^-(hv/kT)=1/e^hv/kT.

now if v(frequency) increases,1/e^hv/kT decreases,and

thus number of oscillators decreases.

Hence there are more oscillators emitting

radiation for lesser values of v,i.e larger

values of lambda(wavelength).Hence more

radiations(more intensity) of shorter

wavelengths are observed since more oscillators

emit these radiations.

And thus at a given temperature T,Intensity

increases with Wavelength in the curve.

If we increase temperature T,value of

fraction 1/e^hv/kT increases and thus consequently

number of oscillators increase.thus even if

wavelengths of radiations are low,

at higher temperature their intensities

will still be higher compared to at

lower temperatures.

Hence at higher T even shorter wavelengths correspond

to high Intensities in the curve.

This explains the curve till maxima,

After the maxima I think the Intensity

falls with increasing wavelength since

now the range of radiations are having too

high a wavelength,the energy for these radiations

is too less,there are not many oscillators

vibrating at this less a frequency...hence

the drop in intensity (bit unsure about this

last para do tell me if wrong)."

-Source,mostly me explaining

some university chemistry study material to

myself.