The sun emits its greatest intensity of radiation in the visible portion of the spectrum. This is because the sun is a hot object, and hot objects emit light with a peak wavelength that is inversely proportional to their temperature. The sun’s surface temperature is about 5,500 Kelvin, which corresponds to a peak wavelength of about 500 nanometers, which is in the visible range.
The infrared portion of the spectrum is just below the visible range, and the ultraviolet portion of the spectrum is just above the visible range. The sun does emit some radiation in these portions of the spectrum, but the intensity is much lower than in the visible range.
The x-ray portion of the spectrum is much higher in energy than the visible range, and the sun does not emit much radiation in this portion of the spectrum.
In conclusion, the sun emits its greatest intensity of radiation in the visible portion of the spectrum.