A helium-neon laser emits light of wavelength 632.8 nm and has a power output of 3 mW.How many photons are emitted per second by this laser? A)9.55 $\times$ 10¹⁴ B)9.55 $\times$ 10¹⁵ C)8.24 $\times$ 10¹⁵ D)6.53 $\times$ 10¹⁵ E)4.78 $\times$ 10¹⁵

Question

Quizplus · Accepted Answer

The number of photons emitted per second can be calculated using the formula:
Number of photons = Power output / Energy of one photon
Energy of one photon = h*c/λ, where h is Planck's constant, c is the speed of light, and λ is the wavelength of the light.

Substituting the given values, we get:
Energy of one photon = (6.626 x 10^-34 J s) * (3 x 10^8 m/s) / (632.8 x 10^-9 m) = 3.14 x 10^-19 J
Number of photons = (3 x 10^-3 W) / (3.14 x 10^-19 J/photon) = 9.55 x 10^15 photons/s

Therefore, the answer is B.

A Helium-Neon Laser Emits Light of Wavelength 632 ×\times× 1014 B)9

A Helium-Neon Laser Emits Light of Wavelength 632 $\times$ 10¹⁴
B)9