Question

For an object producing a thermal spectrum, a higher temperature causes the spectrum to have ___________. a. a peak intensity located at shorter wavelength b. a peak intensity located at longer wavelength c. more prominent emission lines d. more prominent absorption lines

Answer 1

Answer:

a. a peak intensity located at shorter wavelength

Explanation:

We can answer this question by using Wien's displacement law, which relates the temperature of a black body to the peak wavelength of the spectrum of its emitted radiation, as follows:

$\lambda_p T = b$

where:

$\lambda_p$ is the wavelength of the peak of its spectrum

T is the absolute temperature at the surface of the body

$b=2.898\cdot 10^{-3} m\cdot K$ is called Wien's constant

From the equation above, we see that the peak wavelength and the temperature have an inverse relationship. In fact, we can rewrite it as

$\lambda_p = \frac{b}{T}$

By looking at the equation in this form, we can see that the higher the temperature of the object, the shorter the wavelength of its peak: therefore, the correct answer is

a. a peak intensity located at shorter wavelength