ANS:A - Planck's law

The monochromatic emissive power for black body radiation is provided by Wien's law. Wien's law gives the relationship between the temperature of a black body and the wavelength at which it emits the maximum intensity of radiation. It states that the wavelength of maximum emissive power (maxλmax​) is inversely proportional to the absolute temperature (T) of the black body: max=λmax​=Tb​ Where:

• maxλmax​ is the wavelength of maximum emissive power,
• b is Wien's displacement constant (≈2.897×10−3 m⋅K≈2.897×10−3m⋅K),
• T is the absolute temperature of the black body.