The half-life of a positron is very short. It reacts with an electron, and the m
ID: 523773 • Letter: T
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The half-life of a positron is very short. It reacts with an electron, and the masses of both are converted to two gamma-ray photons: 0+1e + 0-1e --> 2gamma This reaction is called an annihilation reaction. The mass of an electron or positron is 9.109*10-31kg. (a) Calculate the energy produced by the reaction between one electron and one positron. Number _______J (b) Assuming that the two gamma-ray photons have the same frequency, calculate this frequency Number gammaphoton = ______Hz
Map General Chemistry 4th Edition University Science Books Quamie Rock Gallogly presented by Sapling Learning e half-life of a positron is very short. It reacts with an electron, and the masses of both are converted to o gam photons This reaction is called an annihilation reaction. The mass of an electron or positron is 9.109 x10 31 kg. (a) Calculate the energy produced by the reaction between one electron and one positron. Number (b) Assu ming that the two Y-ray photons have the same frequency, calculate this frequency Number Hz photonExplanation / Answer
a)
total mass lost = 2* 9.109*10^-31 kg
= 1.8218*10^-30 Kg
This mass is converted to energy
E = m*c^2
= (1.8218*10^-30)*(3*10^8)^2
= 1.63962*10^-13 J
Answer: 1.63962*10^-13 J
b)
2 gamma rays have energy of 1.63962*10^-13 J
energy of 1 gamma ray = 1.63962*10^-13 /2 = 8.1981*10^-14 J
use:
E = h*f
8.1981*10^-14 = (6.626*10^-34)*f
f = 1.237*10^20 Hz
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