(These questions need rewriting!)
1. For 140 keV gammarays the mass attenuation coefficients for hydrogen and oxygen are 0.26
and 0.14 cm^{2}/g respectively. What is the mean free path in water at this
energy:
No, this is not correct.
Yes, this is correct.
No, this is not correct.
2. Consider the graph of absorption vs energy for three types of absorber material. If
the initial energy was 10 MeV, what thickness would the three absorbers have to
be to decrease the intensity by half, given that no buildup occurs and hence all
gammarays
leaving the absorber are detected:
No, this is not correct.
No, this is not correct.
Yes, this is correct.


3. Using the graph above, what will be the energy remaining in an initial beam of 5 MeV
gammarays after passing through 1.0 cm of copper:
No, this is not correct.
Yes, this is correct.
No, this is not correct.
