What was the temperature of the universe when a typical CBR photon was no longer able to spontaneously create an electron and positron pair? Note that a photon has an energy equal to the CBR at any point in time has a blackbody spectrum that peaks at ,and the mass of a single electron is .
A) 2,000 K
B) 400,000 K
C) 4 million K
D) 2 billion K

Question

What was the temperature of the universe when a typical CBR photon was no longer able to spontaneously create an electron and positron pair? Note that a photon has an energy equal to  the CBR at any point in time has a blackbody spectrum that peaks at  ,and the mass of a single electron is  .
A) 2,000 K 
B) 400,000 K 
C) 4 million K 
D) 2 billion K

Quizplus · Accepted Answer

The Answer of What was the temperature of the universe when a typical CBR photon was no longer able to spontaneously create an electron and positron pair? Note that a photon has an energy equal to  the CBR at any point in time has a blackbody spectrum that peaks at  ,and the mass of a single electron is  .
A) 2,000 K 
B) 400,000 K 
C) 4 million K 
D) 2 billion K

What Was the Temperature of the Universe When a Typical