Step 1: Understanding Power
Power is how much energy is used or given out each second. So: Power
=‌| ‌ Energy ‌ |
| ‌ Time ‌ |
Step 2: Energy of One Photon
The energy in one photon of light is found using:
E=hf where
h is Planck's constant and
f is the frequency.
Step 3: Total Energy from Many Photons
If
N photons come out in time
t, the total energy is
N×hf.
Step 4: Linking Power and Number of Photons
So, Power
=‌| ‌ Total Energy ‌ |
| ‌ Time ‌ |
=‌Step 5: Average Number of Photons per Second
The number of photons per second is
n=‌=‌ Plug in the numbers:
n=‌| 33×10−3 |
| 6.6×10−34×5×1014 |
Step 6: Final Calculation
This works out to:
n=10×1016 So, the laser gives off
10×1016 photons every second.
