Verified Solution • 2025–26 Session moderate

QJEEMP_2025_10: JEE Main 2025 Physics - Class 12 JEEMP_2025_10 Solution: An electron projected perpendicular to a uniform magnetic field …

An electron projected perpendicular to a uniform magnetic field B moves in a circle. If Bohr's quantization is applicable, then the radius of the electronic orbit in the first excited state is

Multiple Choice Options

  • A hπeB\sqrt{\frac{h}{\pi e B}}
  • B 4hπeB\sqrt{\frac{4 h}{\pi e B}}
  • C h2πeeB\sqrt{\frac{\mathrm{h}}{2 \pi e \mathrm{eB}}}
  • D 2hπeB\sqrt{\frac{2 h}{\pi e B}}

Step-by-Step Verified Solution

r = mv eB & mvr = nh 2 π ⇒ ( eBr ) r = nh 2 π ⇒ r = nh 2 π eB  first excited state  n = 2 ∴ r = h π eB

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