A blackened platinum wire when gradually heated,first appears dull red,then blue and finally white.Explain.

A blackened platinum wire when gradually heated,first appears dull red

1.	A blackened platinum wire when gradually heated,first appears dull red,then blue and finally white.Explain.
Answer» SOLUTION :According to Wien.s displacement law,the wavelength of maximum emission SHIFTS to lower wavelength region when the temperature is increased.So, the wire turns to DULL RED, them to blue when it is heated.At very high temperature,it emits all radiations strongly and appears white.