## Nuclear medicine, total energy, dose in rem

I cant seem to get this started in the right direction. Any help is appreciated.

As part of a treatment program, a patient ingests a radioactive pharmaceutical containing P32,15, which emits beta rays with an of 1.50. The half-life of is 14.28 , and the initial activity of the medication is 1.34 .

Part A
How many electrons are emitted over the period of 7.00 days?

Part B
If the rays have an energy of 705 keV , what is the total amount of energy absorbed by the patient's body in 7.00 ?

Part C
Find the absorbed dosage in rem, assuming the radiation is absorbed by 110 grams of tissue.

First I converted all times to seconds.

T 1/2 = 1.234e6 s
t = 7 days = 604800 s

Converted activity (RO) into decays per second = 1.34e6

Found N from A-Z = 17

Found decay constant (lambda) = ln(2)/T 1/2 = 5.617e-7

Equations I have tried with no success are N=Noe^-(lambda)(t)

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 Tags dose in rem, initial activity, nuclear medicine, radiation, total energy