According to the Wein's displacement law, the minimum wavelength of the radiated emission is inversely proportional to the absolute temperature of the body which emits radiation.
Where, T is the absolute temperature of the body and λm is the minimum wavelength of heat radiated.
Here, as the temperature increases, the wavelength decreases.
Becasue when you rubbed your hair while you were putting on your sweater it caused it to rub against together causing electricity thingy lol. and thats why your hair goes straigh tup.