i tried em several times and couldnt get the correct answers. only got 2 more attempts for each problems
50fg for this.
#21
A particular radioactive sample undergoes 1.70×106decays/s .
Part A
What is the activity of the sample in curies?
R= ____ Ci
Part B
What is the activity of the sample in becquerels?
Correct answer is R= 1.70*10^6 Bq
100fg each for these.
#36
131I is given to a patient for use in a diagnostic procedure on her thyroid.
What percentage of the 131I sample remains after exactly four days, assuming that all of the 131I is retained in the patient's thyroid gland? (Answer to three significant figures.)
= ____ percent
#32
Part A
Calculate the energy released by the electron-capture decay of 5727Co. Consider only the energy of the nuclei (ignore the energy of the surrounding electrons). The following masses are given:
5727Co: 56.936296u
5726Fe: 56.935399u
Express your answer in millions of electron volts (1u=931.5MeV/c2) to three significant figures.
Correct answer: 0.836 MeV
Part B
A negligible amount of this energy goes to the resulting 5726Fe atom as kinetic energy. About 90 percent of the time, after the electron-capture process, the 5726Fe nucleus emits two successive gamma-ray photons of energies 0.128MeV and 1.60×10−2MeV in decaying to its ground state. The electron-capture process itself emits a massless neutrino, which also carries off kinetic energy. What is the energy of the neutrino emitted in this case?
Express your answer in millions of electron volts.
= ___ MeV