Solve the problems: 1. Find the intensity of an x-ray beam in joules /m2/sec, if the number of photons N in the burst is 1015 through an area A is 0.1m2, and the measurement take place over an interval t is 0.5 sec. The wavelength of x-ray beam is 1010 meters. 2. What thickness (half value layer) of copper will attenuate half of the incident photons at 80kVp. Note: At 80kVp, for copper =6.737cm1. 3. 20keVx-ray rays are generated by the radioactive decay narrow beam case. Using the benchmarks on Figure 14 find approximately the linear attenuation coefficients for bone, muscle, and soft tissue