A proton, an electron, and a Helium nucleus, have the same energy. They are in circular orbitals in a plane due to magnetic field perpendicular to the plane. Let $r_p, r_e$ and $r_{He}$ be their respective radii, then
  • A$r_e > r_p = r_{He}$
  • B$r_e > r_p > r_{He}$
  • C$r_e < r_p < r_{He}$
  • D$r_e < r_p = r_{He}$
JEE MAIN 2019, Medium
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