1.a)The levels of pathogens in meat products such as hamburger can be reduced by irradiating them. If you have 0.8 kg of hamburger, and the maximum allowed dose that can be delivered to the meat is 4.5 kGy, how many 1.5 MeV electrons would it take to reach this limit? Give your answer to 2 s.f.
1.b) Radon undergoes alpha decay with a half-life of 3.8 days. What is its decay constant in s-1?
1.a)
1 kGy = 1 x 103 Gy = 1 x 103 J/Kg
1 J = 6.24 x 1018 eV
The maximum allowed dose that can be delivered to the meat is 4.5 kGy.
1 kg meat can endure 4.5 kGy.
⇒ The amount of radiation 0.8 Kg meat can endure = 0.8 x 4.5 kGy = 0.8 x 4.5 x 103 x 6.24 x 1018 eV
The number of 1.5 MeV electrons it would take to reach this limit = (0.8 x 4.5 x 103 x 6.24 x 1018) eV/ (1.5 x 106) eV
= 14.98 x 1015
b)
Alpha decay follows first order kinetics.
k = 0.693 / t1/2
⇒ k = 0.693 / (3.8 x 24 x 3600)s
= 2.11 x 10-6 s-1
1.a)The levels of pathogens in meat products such as hamburger can be reduced by irradiating them....
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