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PRACTICE · MEMBERSIntermediate · Single correct

PRACTICE / Photon energy and momentum

Power counts many photons

A monochromatic beam has power 3.0 mW. Each photon carries 3.0 × 10⁻¹⁹ J.

Find the photon emission rate.

Organize the givens & assumptions
  • P = 0.003 W
  • Ephoton = 3×10⁻¹⁹ J

Steady monochromatic beam; stated power is entirely carried by photons of the given energy.

  1. A1019 s−110^{19}\ \mathrm{s^{-1}}
  2. B1013 s−110^{13}\ \mathrm{s^{-1}}
  3. C9×10−22 s−19\times10^{-22}\ \mathrm{s^{-1}}
  4. D1016 s−110^{16}\ \mathrm{s^{-1}}

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