Lag1989 problem number 23.17

In what areas of the spectrum are the wavelengths corresponding to the maximum spectral density of energy luminosity, if the light source is: a) a spiral of an electric bulb ( T = 3000K); b) the surface of the Sun (E=6000K); c) an atomic bomb, in which at the moment of explosion a temperature of about 10⁹K develops? The radiation is considered to be close to the radiation of a black body (black body).