Question

The blackbody radiation emitted from a furnace peaks at a wavelength of 7.0 10-6 m (0.0000070 m). What is the temperature inside the furnace?

Answer 1

According to Wien's displacement law, the spectral radiance of black-body radiation per unit wavelength peaks at the wavelength $\lambda = b/T$, where $b = 2.9 \times 10^{-3}\,\text{m K}$ is the Wien's displacement constant. Hence, $T = b / \lambda = 414.3\, \text{K}$ or $414.3 - 273.1 = 141.2\,{}^\circ \text{C}$.

Answer: $414.3\, \text{K}$, or $141.2\,{}^\circ \text{C}$.