No. of photons =(hc/λ)E=6.6×10−34×3×1089×10−3×6.67×10−7=3×1016
Monochromatic light of wavelength 667 ~nm is produced by a helium neon laser. The power emitted is 9 ~mW. The number of photons arriving per second…
NEET UG 2009 — Physics Modern Physics
2009mcqmedium
Monochromatic light of wavelength 667 nm is produced by a helium neon laser. The power emitted is 9 mW. The number of photons arriving per second on the average at a target irradiated by this beam is :
Official previous-year question
Held on 30 Apr 2009 · Verified 9 Jul 2026.
Options
- A
3×1019
- B
9×1017
- C
3×1016
- D
9×1015
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