# Black Body Radiation Help

1. Sep 12, 2013

### kbeach

Hello! I am hoping someone could help.
I have no idea where to start on this, and have been flipping pages for an hour or so trying to figure it out.
Find the spectral range Δλ over which a blackbody's intensity B(1/2) is brighter than half of its peak value B(peak). (In other words, find the difference between the wavelengths where B(1/2) = B(peak)/2)

I have played with the Planck distribution for so long. Am I beating a dead horse? I can't seem to find out what to do with T in the plank distribution, weins law, stefan-bol..... Some guidance please!
Thanks!

Planck Distribution B(λ) = [(2hc^2)/(λ^5)][1/(e^((hc)/(λkT))-1)]
Weins Law λ(max)=b/T

λ=wavelength
T=temperature
c=speed of light
h=planck's constant=6.62606957 × 10-34 (m^2 kg) / s
k=boltzmann constant=1.3806488 × 10-23 (m^2 kg)/(s^2 K)
b=wein's displacement constant=2.897768×10^-3 m K

2. Sep 13, 2013

### Staff: Mentor

Please show your work then.
We cannot see what you did wrong if you don't do that.

I moved your thread to the homework section, as this is a homework-like question.

3. Sep 13, 2013

### kbeach

Hey Sorry I for got to reply! I think i figured it out! Thanks for checking it out!

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