JEE Mains · Physics · STD 12 - 4. Moving charges and magnetism
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 \(r_e < r_p = r_{He}\)
Answer & Solution
Correct Answer
(D) \(r_e < r_p = r_{He}\)
Step-by-step Solution
Detailed explanation
\(r=\frac{m v}{q B}=\frac{\sqrt{2 m K}}{q B}\) \(r_{\mathrm{He}}=r_{p}>r_{e}\)
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