According to the black body radiation theory wavelength of light decreases with increase in temperature whereas the frequency increases.
The wavelength keeps decreasing till absolute hot where it becomes 0 and the frequency becomes infinite. Thus in the radiations emitted from such a body have no electric and magnetic fields oscillating and they become coincident along the direction of motion of radiation.
This makes sense as theories suggest that Electric & Magnetic fields were same at the beginning of the universe. Conversely if the first assumption is false then it means there is a maximum frequency and minimum wavelength of radiation possible beyond which we cannot go.
By the way I am just starting out. Please be merciful in explanations.