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songoku
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Homework Statement
The radioactive isotope radon-222 may decay spontaneously by emitting an alpha particle. The daughter nucleus is an isotope of polonium. The atomic masses of these isotopes are:
Rn-222 : 222.0157 u
Po : 218.00896 u
He : 4.00260 u
A sample of radon-222 contains 3.0 x 107 nuclei. The total energy that will be release in a time interval of 3 T1/2 through alpha decay of the radon-222 is:
a. 3.856 MeV
b. 5.785 x 107 MeV
c. 8.677 x 107 MeV
d. 1.012 x 108 MeV
e. 1.085 x 108 MeV
Homework Equations
E = mc^2
T1/2 = (ln 2) / λ
The Attempt at a Solution
If the question asks only for one half-life then the energy released = (mass of Rn - mass of Po - mass of He) x 931.5 MeV. Is this correct?
I don't know how the time interval of 3 half-life and number of nuclei play part in this question. Are they used to find energy released or they are only redundant information?
Thanks