Final answer:
The percentage of 80-keV photons attenuated by a 4 cm thick slab of bone is approximately 90%.
Step-by-step explanation:
To determine the percentage of 80-keV photons attenuated by a 4 cm thick slab of bone, we need to consider the concept of linear attenuation coefficient. The linear attenuation coefficient is a measure of how much a material attenuates a beam of photons. It is denoted by the symbol mu (μ).
The equation used to calculate the percentage of photons attenuated is: percentage of photons attenuated = (1 - e^(-μx)) x 100, where e is the base of the natural logarithm and x is the thickness of the material. Given that the density of bone is 1.8 g/cm^3 and using the mass attenuation coefficient for bone at 80 keV, we can calculate the linear attenuation coefficient (μ) for bone.
Using the equation for linear attenuation coefficient (μ = mass attenuation coefficient / density), we can find μ. Once we have μ, we can substitute it into the equation to calculate the percentage of photons attenuated. After performing these calculations, it is determined that approximately 90% of the photons will be attenuated by the 4 cm thick slab of bone. Therefore, the correct answer is d) 90%.