The Current Temperature of the Cosmic Background Radiation of 2 $\mu$

Multiple Choice

The current temperature of the cosmic background radiation of 2.73 K means that the peak of its spectrum occurs at a wavelength of:

A) 0.1 $\mu$ m
B) 1 $\mu$ m
C) 10 $\mu$ m
D) 100 $\mu$ m
E) 1,000 $\mu$ m