I am looking at the wikipedia article of the Planck's law. Is the second formula correct? $$ B_\lambda (\lambda, T) = \frac{2hc^2}{\lambda^5}\frac{1}{e^\frac{hc}{\lambda k_B T} -1} $$
If $f = \frac{c}{\lambda}$, should it not look like this? $$ B_\lambda (\lambda, T) = \frac{2hc}{\lambda^3}\frac{1}{e^\frac{hc}{\lambda k_B T} -1} $$
