The wavelength of the K_$\alpha$ X-ray line for an element is 0.0794 nm.The atomic number of the element is A)36 B)38 C)40 D)42 E)44

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The wavelength of the Kα X-ray line can be related to the atomic number (Z) of an element using Moseley's law, which states that the square root of the frequency of the emitted X-ray is proportional to the atomic number of the element. The formula derived from Moseley's law for the Kα line is: $\sqrt{\nu} = a(Z - b)$, where $\nu$ is the frequency, $a$ and $b$ are constants, and $Z$ is the atomic number. Since frequency ($\nu$) and wavelength ($\lambda$) are inversely related ($\nu = c/\lambda$, where $c$ is the speed of light), we can substitute $\nu$ with $c/\lambda$ in the formula. Given the wavelength ($\lambda$) is 0.0794 nm, we can calculate the approximate atomic number. The exact calculation involves more detailed constants and conversion of units, but knowing the general trend and the given options, the atomic number that corresponds to the given wavelength is closest to the atomic number of strontium (Sr), which is 38. This is a simplified explanation; precise calculations would require using the specific values of the constants in Moseley's law and converting the wavelength to the appropriate units to match those constants.

The Wavelength of the K α\alphaα X-Ray Line for an Element Is 0

The Wavelength of the K_$\alpha$ X-Ray Line for an Element Is 0