Multiple Choice
What was the temperature of the universe when a typical CMB photon was no longer able to spontaneously create an electron and positron pair? Note that a photon has an energy equal to E = hc/λ,the CMB at any point in time has a blackbody spectrum that peaks at a wavelength λpeak = (2900 μm K) /T,and the mass of a single electron is 9 × 10−31 kg.
A) 2000 K
B) 400,000 K
C) 2 million K
D) 40 million K
E) 2 billion K
Correct Answer:
Verified
Correct Answer:
Verified
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