Electromagnetic radiation with a wavelength of 641 nm appears as orange light to the human eye. the energy of one photon of this light is 3.10 × 10−19 j. thus, a laser that emits 1.3×10−2 j of energy in a pulse of light at this wavelength produces photons in each pulse.

4.19×10¹⁶

Explanation:

λ = Wavelength = 641 nm

E = Energy of one photon = 3.1×10⁻¹⁹ J

Energy of laser = 1.3×10⁻² J

n = Number of photons

Energy of laser = n×Energy of one photon

Number of photons is 4.19×10¹⁶.

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