Hello Aspirant,

the wavelength of the radiation emitted by a blackbody depends upon the temperature of surface from which radiations are being emitted because according to wien's displacement law as temperature of body increases, the maximum intensity of emissions shifts towards shorter wavelength.

λT=b(constant)

where, λ is the wavelength at which maximum emission takes place at absolute temperature T.

I hope this information cleared your doubts.

Good Luck!!