Explain the color changes in a hot body as its temperature is increased.

A hot body emits electromagnetic radiation due to its temperature, and this phenomenon is known as blackbody radiation. As the temperature of the body increases, the intensity and distribution of emitted wavelengths of light change. This causes the overall color of the object to change as well.

Wien's Law helps us understand the relationship between temperature and the peak wavelength of emitted radiation. It is given by the formula: \(\lambda_{max} = \frac{b}{T}\) where \(\lambda_{max}\) is the peak wavelength, \(T\) is the temperature in Kelvin, and \(b\) is Wien's constant, approximately equal to \(2.898 \times 10^{-3} m \cdot K\). According to this law, as temperature increases, the peak wavelength of emitted radiation shifts to shorter wavelengths. We can use this formula to mathematically predict how the color changes as the temperature of the body increases.

Colors of the objects are perceived based on the wavelengths of the light it emits or reflects. The visible light spectrum has wavelengths ranging from 380 nm (violet) to 750 nm (red). Since Wien's Law tells us how the peak wavelength changes with temperature, we can correlate the color changes of the hot object to the visible light spectrum. As seen in the spectrum, shorter wavelengths correspond to blue and violet colors, and longer wavelengths correspond to red and orange colors.

Using Wien's Law and the visible light spectrum, we can outline the following color changes in a hot body as its temperature is increased: 1. At lower temperatures (below 1000 K), most radiation emitted by the object is in infrared range, which is not visible to the human eye. Thus, the object appears dark at these temperatures. 2. As the temperature increases to around 1000 K, the peak wavelength enters the visible light spectrum, with a reddish-orange color. 3. As the temperature further increases, the peak wavelength shifts towards shorter wavelengths. The color of the object progressively changes from red, orange, yellow, white, and eventually blue as the temperature keeps increasing. By understanding blackbody radiation and Wien's Law, we can explain the color changes in a hot body as its temperature is increased. The object's color changes from reddish-orange to blue as the temperature rises, due to the shift in peak wavelength towards shorter wavelengths in the visible light spectrum.