How many photons per second are emitted by a 7.50-mW CO2 laser that has a wavelength of 10.6 mm?

Video transcript

Welcome back, everyone. We are making observations about an argon ion and we are told that the laser argon ion laser delivers a laser beam output with a wave length of 488 nanometers or 488 times 10 to the negative ninth meters. Now, we are also told that it's emitted at a power of two watts. And we are tasked with finding the number of photons emitted per second by this laser. Well, we have that our power is equal to our total energy divided by time. We know however, that our total energy is equal to the number of photons times our energy divided by our time. So rearranging our equation here, what we get is that our rate of photons emitted per second is equal to our power divided by our energy. We know our power. But what is going to be our energy? In this case, let me change colors real quick. We have that our energy is equal to planks constant times the speed of light divided by our wavelength, we have all of these values. So let's go ahead and calculate that we have that our energy is equal to 6.63 times 10 to the negative 34 times three times 10 to the eighth, all divided by our wavelength of 488 times 10 to the negative ninth. What this gives us is four point oh eight times 10 to the negative 19th Jews. So now we are ready to find the number of photons emitted per second. So we have that our rate is equal to two divided by four point oh eight times 10 to the negative 19th, which when we plug it into our calculator gives us a final answer of 4.9 times to the 18th photons per second corresponding to our final answer. Choice of D Thank you all so much for watching. I hope this video helped. We will see you all in the next one.