Biomedicine: A 70-kg laboratory technician absorbs 2.9 mJ of 0.50-MeV gamma rays in a workday. How many gamma-ray photons does the technician absorb in a workday?

Question

Quizplus · Accepted Answer

The energy of a single gamma-ray photon is:$$E = hf = \frac{hc}{\lambda}$$where h is Planck's constant, f is the frequency, c is the speed of light, and lambda is the wavelength.The wavelength of a 0.50-MeV gamma ray is:$$\lambda = \frac{hc}{E} = \frac{(6.626 	imes 10^{-34} 	ext{ J s})(3 	imes 10^8 	ext{ m/s})}{5.0 	imes 10^5 	ext{ eV}} = 2.49 	imes 10^{-12} 	ext{ m}$$The number of gamma-ray photons absorbed by the technician is:$$N = \frac{E}{E_\gamma} = \frac{2.9 	imes 10^{-3} 	ext{ J}}{5.0 	imes 10^5 	ext{ eV}} = 3.6 	imes 10^{10}$$

Biomedicine: a 70-Kg Laboratory Technician Absorbs 2