Explain how the accelerating voltage in the X-ray tube controls the hardness of an X-ray beam.
For a parallel beam of X-ray radiation, attenuation is described by $\frac{I}{I_0} = e^{-\mu x}$, where $\mu$ is the linear attenuation (absorption) coefficient and $x$ is the thickness of the material through which the beam passes. State what is meant by attenuation.
For a parallel beam of X-ray radiation, the attenuation is given by $\frac{I}{I_0} = e^{-\mu x}$. Explain why this expression is valid only for a parallel beam.
The linear attenuation coefficients for X-rays in bone and in soft tissue are $2.9\,\text{cm}^{-1}$ and $0.95\,\text{cm}^{-1}$ respectively. Calculate, for a parallel X-ray beam, the ratio $\dfrac{\text{fraction } \frac{I}{I_0} \text{ of intensity transmitted through bone of thickness } 2.5\text{ cm}}{\text{fraction } \frac{I}{I_0} \text{ of intensity transmitted through soft tissue of thickness } 6.0\text{ cm}}.$