3. Radiation

Blackbody Radiation — Quiz

Test your understanding of blackbody radiation with 5 practice questions.

Practice Questions

Question 1

The classical Rayleigh-Jeans Law successfully described blackbody radiation at long wavelengths but failed dramatically at short wavelengths. What was the primary conceptual flaw in the classical derivation that led to the 'ultraviolet catastrophe'?

Question 2

The Planck function for spectral radiance is given by $B_{\nu}(T) = \frac{2h\nu^3}{c^2} \frac{1}{e^{h\nu/k_B T} - 1}$. What physical interpretation can be given to the term $\frac{1}{e^{h\nu/k_B T} - 1}$ in the context of quantum statistics?

Question 3

Consider a spherical blackbody with radius $R$ and temperature $T$. If its radius is doubled to $2R$ and its temperature is halved to $\frac{T}{2}$, how does its total luminosity change?

Question 4

A protostar is observed to have a peak emission wavelength of $10 \text{ \mu m}$. If it contracts and heats up, and its new peak emission wavelength is $2 \text{ \mu m}$, by what factor has its temperature increased?

Question 5

In the context of cosmic backgrounds, how does the Cosmic Microwave Background (CMB) differ from other cosmic backgrounds (e.g., Cosmic Infrared Background, Cosmic X-ray Background) in terms of its blackbody nature?