An electron gun is placed inside a long solenoid of radius $\mathrm{R}$ on its axis. The solenoid has $\mathrm{n}$ turns/length and carries a current $I$. The electron gun shoots an electron along the radius of the solenoid with speed $v$. If the electron does not hit the surface of the solenoid, maximum possible value of ${v}$ is (all symbols have their standard meaning)

830-1302

  • [JEE MAIN 2020]
  • A

    $\frac{\mathrm{e} \mu_{0} \mathrm{nIR}}{\mathrm{m}}$

  • B

    $\frac{\mathrm{e} \mu_{0} \mathrm{nIR}}{2 \mathrm{m}}$

  • C

    $\frac{2 \mathrm{e} \mu_{0} \mathrm{nIR}}{\mathrm{m}}$

  • D

    $\frac{\mathrm{e} \mu_{0} \mathrm{nIR}}{4 \mathrm{m}}$

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