Question

Cosmic background radiation. The following figure shows measurements of the energy density of the background cosmic radiation. The graphical quantity is the spectral density as a function of the energy per unit volume according to the relationship: di / dw = cu(w) / 41 Assuming Planck's Law, estimate the temperature of the background cosmic radiation. Use that lerg = 10-7 J, kg = 1.38 x 10-23 J/K y c~ 10%m/s. -3.00 30 Wavelength (cm) 0.3 0.03 10-14 10-15 10-16 10-17 Intensity (erg/sec/cm° /sr/Hz) • Ground-Based • Balloon • Cyanogen • COBE DMR — COBE/FIRAS 0.1 1 100 1000 10 Frequency (GHz)

Answer 1

finen the peck inten ting frepueney Frm the can Curve nsi occuus that Bee at 160 GH2 Planck law Now us Can the fregaary temperatme reation Bhow that the freruncy temperatune selation Comes out be to 2.8214 KT

2.8214 K 6.626X10-34 X 160 x109 23 2.8214 X 1-38 X 10 the f temper adume 2.72 3 K CMB - radiati on