The body that absorbs all radiations that are falling is one of the property of a black body.The graph for intensity and wavelength of a black body is shown in the attached figure. The intensity depends on the temperature of the body. From the figure it is clear that the peak of intensity of our sun is in visible region.
The Stefan-Boltzmann law gives the relationship between the temperature and the wavelength of any body. So, the wavelength of the highest peak of intensity is in between 400 nm to 700 nm.
