Question

Assertion (A) Iron rod is heated in furnace, it first turns to dull red, intense red, white and then become blue as the temperature becomes high.
Reason (R) The frequency of emitted radiation goes from a higher frequency to a lower frequency as the temperature increases.

• A. Both $A$ and $R$ are correct; $R$ is the correct explanation of $A$.
• B. Both $A$ and $R$ are correct; $R$ is not the correct explanation of $A$.
• C. $A$ is correct; $R$ is incorrect.
• D. $A$ is incorrect; $R$ is correct.

Answer 1

Answer: (C)

When an iron rod is heated in a furnace, it first turns to dull red and become more red as the temperature increases. it becomes white and then blue as the temperature become very high.
Frequency of emitted radiation goes from lower frequency to higher frequency as the temperature increases.
The red colour lies in the lower frequency while blue colour belongs to the higher frequency region of electromagnetic spectrum.
Thus, $A$ is correct but $R$ is incorrect.