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Potassium-40 can decay in three modes .I...

Potassium-40 can decay in three modes .It can decay by `beta^(-)` - emission,`beta^(+)` -emission or electron capature. (a) Write the equation showing the end products. (b) Find the Q-value in each of the three cases. Atomic masses of `Ar_18^40`,`K_19^40`and `Ca_20^40` are 39.9624 u,39.9640 u,and 39.9626 u respectively.

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[(a) `._(19)^(40)K rarr ._(20)^(40)Ca + e^(-) + bar(v), ._(19)^(40)K rarr ._(18)^(40)Ar + e^(+) +v, ._(19)^(40)K + e^(-1) rarr ._(18)^(40)Ar+v` (b) 1.3034 MeV, 0.4676 MeV, 1.490 MeV]
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