The Energy of Light Video Lessons

Concept: The Energy of Light

# Problem: X-ray diffractometers often use metals that have had their core electrons excited as a source of X rays. Consider the 2p → 1s transition for copper, which is called the Kα transition. Calculate the wavelength of X rays (in angstroms) given off by the Kα transition if the energy given off by a mole of copper atoms is 7.77 × 105 kJ . (Note that 1Å = 10-10 m)

###### FREE Expert Solution

Calculate the energy in J/photon:

E = 1.29× 10–15 J/atom = 1.29× 10–15 J/photon

Calculate wavelength:

$\overline{){\mathbf{E}}{\mathbf{=}}\frac{\mathbf{hc}}{\mathbf{\lambda }}}$

$\mathbf{\lambda }\mathbf{=}\frac{\mathbf{hc}}{\mathbf{E}}$

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###### Problem Details

X-ray diffractometers often use metals that have had their core electrons excited as a source of X rays. Consider the 2→ 1s transition for copper, which is called the transition. Calculate the wavelength of X rays (in angstroms) given off by the transition if the energy given off by a mole of copper atoms is 7.77 × 105 kJ . (Note that 1Å = 10-10 m)