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Question
The figure shows the intensity-wavelength relations of X-rays coming from two different Coolidge tubes. The solid curve represents the relation for the tube A in which the potential difference between the target and the filament is VA and the atomic number of the target material is ZA. These quantities are VB and ZB for the other tube. Then,
Options
VA > VB, ZA > ZB
VA > VB, ZA < ZB
VA < VB, ZA > ZB
VA > VB, ZA < ZB
Solution
VA > VB, ZA < ZB
It is clear from the figure that the X-ray of tube A has less cutoff wavelength than the X-ray of tube B.
`therefore lambda_A < lambda_B`
Using Moseley's Law,
`Z_A < Z_B`
`lambda ∝ 1/V` , where V is the voltage applied in the X-ray tube.
`therefore V_A > V_B`
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