A piece of iron is heated in a flame. It first comes dull red then becomes reddish yellow and finally turns to white hot. The correct explanation for the above observation is possible by using

Options

(a) Wien’s displacement law
(b) Kirchoff’s law
(c) Newton’s law of cooling
(d) Stefan’s law

Correct Answer:

Wien’s displacement law

Explanation:

Wien’s displacement law, According to this law,
λmax ∞ 1 / T or λmax x T = constant. So, as the temperature increases λ decreases.