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STD 12 - 12. atoms — JEE STD 11 Science — Question

Gujarat BoardEnglish MediumSTD 11 ScienceJEESTD 12 - 12. atoms4 Marks
MCQ
Solid targets of different elements are bombarded by highly energetic electron beams. The frequency $(f)$ of the characteristic $X-$ rays emitted from different targets varies with atomic number $Z$ as
  • A
    $f \propto \sqrt Z $
  • ✓
    $f \propto {Z^2}$
  • C
    $f \propto {Z}$
  • D
    $f \propto {Z^{3/2}}$
✓

Answer

Correct option: B.
$f \propto {Z^2}$
b
From Mosley law,
$f = a (Z -b)^2$
$f \propto Z^2$

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