Wien's law and the colour of a hot body

As a body gets hotter it glows dull red, then orange, then white. You will make the program find the wavelength of strongest radiation and the power from each square metre for temperatures from $300\ \text{K}$ to $10\,000\ \text{K}$, and the lowest temperature whose strongest radiation is visible.

The idea. Wien: $\lambda_m = \dfrac{b}{T}$, $b = 2.90 \times 10^{-3}\ \text{m K}$. Stefan: $\dfrac{P}{A} = \sigma T^4$. Visible light runs from about $400\ \text{nm}$ to $700\ \text{nm}$.

Your tasks.

1. Work out lam, the wavelength of strongest radiation in nm, for every temperature in T.
2. Work out flux, the power from each square metre, in watts.
3. Find the lowest temperature in T whose lam is at most $700\ \text{nm}$.