- #1

FaraDazed

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## Homework Statement

A blackbody has a peak wavelength of 2x10^-6m , use the wavelength form of Wiens Law to calculate its temperature

## Homework Equations

[tex]

\lambda_{peak}=\frac{hc}{5kT} \\

I_{\lambda}=\frac{2hc^2}{\lambda^5(e^{hc/ \lambda kT}-1)}

[/tex]

## The Attempt at a Solution

I was not sure what equation to use but from the lecture booklet the two above are the only ones with temperature in them, the second one doesn't give me enough information as I don't know [itex]I_{\lambda}[/itex], however my answer just doesn't seem correct to me.

[tex]

\lambda_{peak}=\frac{hc}{5kT} \\

2×10^{-6}=\frac{(6.626×10^{-34})(2.997×10^8)}{5(1.38×10^{-23})T} \\

2×10^{-6}=\frac{1.986×10^{-25}}{(6.98×10^{-23})T} \\

T(6.98×10^{-23})(2×10^{-6})=1.986×10^{-25} \\

T(1.396×10^{-28})=1.986×10^{-25} \\

T=\frac{1.986×10^{-25}}{1.396×10^{-28}}=1422K

[/tex]

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