Which colour of heat radiation represents the highest temperature?

The color of heat radiation emitted by a body is directly related to its temperature, a principle described by Wien's displacement law. According to this law, as the temperature of an object increases, the peak wavelength of the emitted radiation shifts to shorter wavelengths [1]. Planck's law further confirms that hotter bodies radiate more energy at shorter wavelengths [1]. In the sequence of thermal radiation colors, 'red hot' represents the lower end of the visible spectrum. As the temperature rises, the object transitions through cherry red and salmon to 'white hot' [1]. White light is a combination of all visible wavelengths, indicating that the object is emitting significant energy across the entire visible spectrum, which occurs at much higher temperatures than those producing distinct red or orange hues. Therefore, white represents the highest temperature among the given options.

Sources

1. [1] FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.) > Chapter 8: Solar Radiation, Heat Balance and Temperature > INVERSION OF TEMPERATURE > p. 73