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Question
Find the maximum potential difference which may be applied across an X-ray tube with tungsten target without emitting any characteristic K or L X-ray. The energy levels of the tungsten atom with an electron knocked out are as follows.
| Cell containing vacancy | K | L | M |
| Energy in keV | 69.5 | 11.3 | 2.3 |
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Solution
Let the potential required that may be applied across the X-ray tube without emitting any characteristic K or L X-ray be V.
∴ Energy of electron = eV
This amount of energy is equal to the energy of L shell.
So, the maximum potential difference that can be applied without emitting any electron is 11.3 kV.
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