The cosmic microwave background radiation forms a blackbody curve corresponding to a temperature of 2.73 K. What does Wien's law predict for the peak wavelength in this blackbody curve?
A) 0.654 mm
B) 1.07 mm
C) 21.1 cm
D) 2.73 m

Question

Quizplus · Accepted Answer

Wien's law states that the peak wavelength of a blackbody curve is inversely proportional to its temperature. The law is given by $\lambda_{\text{max}} = \frac{b}{T}$, where $b$ is Wien's displacement constant ($2.897 \times 10^{-3} m \cdot K$). For a temperature of 2.73 K, the peak wavelength $\lambda_{\text{max}}$ is calculated as $\frac{2.897 \times 10^{-3} m \cdot K}{2.73 K} \approx 1.06 \times 10^{-3} m$ or 1.06 mm, which rounds to 1.07 mm, matching choice B.

The Cosmic Microwave Background Radiation Forms a Blackbody Curve Corresponding