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Electron, Photon, Photo-electric Effect and X-Rays — JEE physics STD 12 Science — Question

CBSE BoardEnglish MediumSTD 12 ScienceJEE physicsElectron, Photon, Photo-electric Effect and X-Rays1 Mark
MCQ
In producing $X$-rays a beam of electrons accelerated by a potential difference $V$ is made to strike a metal target. For what value of $V, X$ rays will have the lowest wavelength of $0.3094 \mathring A$
  • A
    $10 \mathrm{kV}$
  • B
    $20 \mathrm{kV}$
  • C
    $30 \mathrm{kV}$
  • ✓
    $40 \mathrm{kV}$
✓

Answer

Correct option: D.
$40 \mathrm{kV}$
From the formula$V=\frac{12375}{\lambda_{\min }}=\frac{12375}{0.3094}=39.99 \mathrm{kV} \approx 40 \mathrm{kV}$

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