Class 11 NEET Physics Properties of Matter Questions

According to Wien’s displacement law
λmT=constant
λm=

constant

T

So when a piece of iron is heated, λm decreases i.e. with rise in temperature the maximum intensity of radiation emitted gets shifted towards the shorter wavelengths. So the colour of the heated object will change that of longer wavelength (red) to that of shorter (reddish yellow) and when the temperature is sufficiently high and all wavelengths are emitted, the colour will become white.