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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
An electron beam is moving between two parallel plates having electric field $1.125 \times 10^{-6} \mathrm{~N} / \mathrm{m}$. A magnetic field $3 \times 10^{-10} \mathrm{~T}$ is also applied so that beam of electrons do not deflect. The velocity of the electron is
  • A
    $4225 \mathrm{~m} / \mathrm{s}$
  • ✓
    $3750 \mathrm{~m} / \mathrm{s}$
  • C
    $2750 \mathrm{~m} / \mathrm{s}$
  • D
    $3200 \mathrm{~m} / \mathrm{s}$
✓

Answer

Correct option: B.
$3750 \mathrm{~m} / \mathrm{s}$
$v=\frac{E}{B}=\frac{1.125 \times 10^{-6}}{3 \times 10^{-10}}=3750 \mathrm{~m} / \mathrm{s}$

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