Final answer:
To calculate the number of photons in a 4.4 mJ pulse, we first need to find the energy of each photon. Using the equation E = hf, we can determine the photon energy using the given wavelength. Then, we divide the total energy by the energy of each photon to find the number of photons. The answer is option A. 1.23 x 10^16.
Step-by-step explanation:
The photon energy can be calculated using the equation:
E = hf
Where E is the energy, h is Planck's constant, and f is the frequency.
Given the wavelength of 555 nm, we can calculate the frequency using the speed of light equation:
c = λf
Where c is the speed of light and λ is the wavelength. Rearranging the equation, we get:
f = c/λ
Substituting the values, we get:
f = (3 x 10^8 m/s) / (555 x 10^-9 m) = 5.405 x 10^14 Hz
Now, we can calculate the energy:
E = hf = (6.63 x 10^-34 J.s)(5.405 x 10^14 Hz) = 3.58 x 10^-19 J
To find the number of photons in a 4.4 mJ pulse, we divide the total energy by the energy of each photon:
Number of photons = (4.4 x 10^-3 J) / (3.58 x 10^-19 J) = 1.23 x 10^16
Therefore, the answer is option A. 1.23 x 10^16.