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Question: Answered & Verified by Expert
An electron and a photon have same wavelength of $10^{-9} \mathrm{~m}$. If $\mathrm{E}$ is the energy of the photon and $\mathrm{p}$ is the momentum of the electron, the magnitude of $\mathrm{E} / \mathrm{p}$ in SI units is
PhysicsDual Nature of MatterKVPYKVPY 2016 (SB/SX)
Options:
  • A $1.00 \times 10^{-9}$
  • B $1.50 \times 10^{8}$
  • C $3.00 \times 10^{8}$
  • D $1.20 \times 10^{7}$
Solution:
1755 Upvotes Verified Answer
The correct answer is: $3.00 \times 10^{8}$
Energy of photon $=\mathrm{E}=\frac{\mathrm{hc}}{\lambda}$
Momentum of photon $=\mathrm{P}=\frac{\mathrm{h}}{\lambda}$
$\mathrm{E}=\mathrm{PC} \quad \therefore \frac{\mathrm{E}}{\mathrm{P}}=\mathrm{C}=3 \times 10^{8} \mathrm{~m} / \mathrm{s}$

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