Spectral irradiance of a black body as defined by Planck's law: $$I\left(\lambda, T\right) = \frac{2{\pi}hc^2}{\lambda^5}\frac{1}{\exp\left(\displaystyle\frac{hc}{{\lambda}kT}\right) - 1}$$ where $$h$$ is the Planck constant, $$c$$ is the speed of light, and $$k$$ is the Boltzmann constant. Explore the behaviour of the spectral irradiance by manipulating the black body temperature using the slider below: