To
determine the number of photons emitted per second, we need data on the total
power of the system and the total energy of the photons. We use this concept to calculate the wavelength. We are given the power of the laser, the time and the number of photons that was emitted for that given time. We calculate as follows:
Number of photons = 1.51×10^20 per hour
Number of photons per second = 1.51 x 10^20 / hr ( 1 hr / 3600 s ) = 4.19 x 10^16 per second
4.19 x 10^16 per second = Power / Energy
4.19 x 10^16 per second = 20x10^-3 J / s / Energy
Energy = 4.77x10^-19 J
Energy
= hc / wavelength<span>
where h is the planck's constant and c is the
speed of light
</span>4.77x10^-19 J <span>= (6.63 x 10^-34)
(3 x 10^8) / wavelength
Wavelength = 4.17x10^-7 m
</span>
