a. A patient's chest is exposed to X-rays, and the X-rays passing through the patient are recorded on a photographic film to generate an X-ray image of the chest for medical diagnosis. The average wavelength of X-rays in chest radiology is about 0.5 A (0.05 nm). Numerous measurements indicate that the patient, on average, is exposed to total radiation energy per unit area of roughly 0.1 µJ cm? for one chest X-ray image. Find the photon energy used in chest radiology, and the average number of photons incident on the patient per unit area (per cm?). b. Please use the wave behaviour of electrons and the associated energy band structure to explain the conduction mechanism in metal with/without external applied electric field. c. Please use the energy band structure to explain the difference among conductor, semiconductor and insulator.

a. A patient's chest is exposed to X-rays, and the X-rays passing through the patient are recorded on a photographic film to generate an X-ray image of the chest for medical diagnosis. The average wavelength of X-rays in chest radiology is about 0.5 A (0.05 nm). Numerous measurements indicate that the patient, on average, is exposed to total radiation energy per unit area of roughly 0.1 µJ cm? for one chest X-ray image. Find the photon energy used in chest radiology, and the average number of photons incident on the patient per unit area (per cm?). b. Please use the wave behaviour of electrons and the associated energy band structure to explain the conduction mechanism in metal with/without external applied electric field. c. Please use the energy band structure to explain the difference among conductor, semiconductor and insulator.