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Q87 (CDS-II/2007) Science & Technology › Basic Science (Physics, Chemistry, Biology) › Thermal physics Answer Verified

Which colour of heat radiation represents the highest temperature?

Result
Your answer: —  Â·  Correct: D
Explanation

The color of a glowing object is directly related to its temperature through Wien's displacement law, which states that the peak wavelength of radiation is inversely proportional to the absolute temperature [t1][t4]. As an object is heated, it first emits infrared radiation, then progresses through visible colors starting from 'red hot' (longer wavelengths) to orange and yellow [t2][t7]. At higher temperatures, the object emits radiation across the entire visible spectrum, appearing 'white hot' [t5]. For instance, a blackbody at 1000 K appears red, while one at 6000 K appears white [t4]. Among the options provided, 'blood red' and 'dark cherry' represent lower temperatures in the incandescence spectrum, while 'salmon' (orange-pink) is intermediate. 'White' represents the highest temperature because the emission peak has shifted toward shorter wavelengths and covers the full visible range [t5][t6].

Sources

  1. [1] https://en.wikipedia.org/wiki/Wien%27s_displacement_law
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