RE-NEET2026Physics-Modern Physics
RE-NEET 2026 Physics Photon and Electron Momentum MCQ Question
Type: MCQ-numerical-Hard
A photon and an electron, each of 20 eV energy, move in free space. The ratio of linear momentum of electron pₑ to that of photon p_ph is: (Take speed of light = 3×10⁸ ms⁻¹, charge of electron = -1.6×10⁻¹⁹ C and mass of electron = 9×10⁻³¹ kg)
A
1/250
B
225
C
275
D
2/450
Correct Answer
Option A
Detailed Explanation
The momentum of a photon is given by p_ph = E/c, and for an electron, pₑ = √(2mE). Calculating both and taking the ratio gives 1/250.
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