2. Choose the correct answer Initial X-ray flux is attenuated I in a substance , in accordance with the law: Phi =Phi _(0)e^-mu x Phi =Phi _(0)mu x^-2 Phi =Phi _(0)/mu x Phi =Phi _(0)(-ln(mu x))

The correct answer is: $\Phi =\Phi _{0}e^{-\mu x}$<br /><br />Explanation: The given equation represents the attenuation of the initial X-ray flux ($\Phi_0$) in a substance, where $\mu$ is the attenuation coefficient and $x$ is the thickness of the substance. The correct equation is $\Phi = \Phi_0 e^{-\mu x}$, which describes the exponential decay of the flux as it passes through the substance.