Question

Given: 1eV=1.6×10^-19 Joules, 1Ci=3,7×10¹⁰ des/s.

A 2 mCi of ⁶⁰Co source emits two gamma rays per disintegration with energies of E₁=1172 and E₂=1332 keV. 10% of gamma rays emitted from the source have been fully absorbed in a cube with a 10 cm side and a density of r = 2g/cm³.

The mass of the cube is m=r.V, where V is the volume of the cube.

Do your calculation and circle the correct answer for:

• The number of gammas per second, N_g, emitted by the ⁶⁰Co source at t=0.
• The absorbed dose D in the cube for 10 minutes exposure, in Gy
• The absorbed dose rate D in the cube, in Gy/hr.

1. N_g = 74×10⁶ g/s, D = 889×10^-6Gy, D = 0.534×10^-5Gy/h
2. N_g = 148×10⁶ g/s, D = 88.9×10^-6Gy, D = 534×10^-5Gy/h
3. N_g = 148×10⁶ g/s, D = 8.89×10^-6Gy, D = 5.34×10^-5Gy/h
4. None of the above

Answer 1

Since none of the options match the obtained answers, the correct answer is None of the above.