Study Smarter: Calculating Photon Emission from Helium-Neon Laser
How many photons are emitted per second by a 1.0 mW helium-neon laser with a wavelength of 633 nm?
The 1.0 mW helium-neon laser emits approximately 3.19 × 10^15 photons per second.
Calculating Photon Emission
Number of photons emitted per second = Power of the laser / Energy of each photon
The energy of each photon can be calculated using the equation:
Energy of each photon = (Planck's constant * speed of light) / wavelength
Where:
Planck's constant (h) = 6.62607015 × 10^(-34) J·s
Speed of light (c) = 2.998 × 10^8 m/s
Wavelength (λ) = 633 nm = 633 × 10^(-9) m
First, let's calculate the energy of each photon:
Energy of each photon = (6.62607015 × 10^(-34) Js * 2.998 × 10^8 m/s) / (633 * 10^(-9) m)
Energy of each photon ≈ 3.1357 × 10^(-19) J
Now, let's calculate the number of photons emitted per second:
Number of photons emitted per second = (1.0 * 10^(-3) W) / (3.1357 * 10^(-19) J)
Number of photons emitted per second ≈ 3.19 × 10^15 photons
Therefore, the 1.0 mW helium-neon laser emits approximately 3.19 × 10^15 photons per second.