Alaser produces 20.0 mw of light. in 1.00 hr , the laser emits 1.51×1020 photons. what is the wavelength of the laser?

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

where h is the planck's constant and c is the speed of light

4.77x10^-19 J = (6.63 x 10^-34) (3 x 10^8) / wavelength
Wavelength = 4.17x10^-7 m

most historians agree that gabriel mouton, the vicar of st. paul’s church in lyons, france, is the “founding father” of the metric system. he proposed a decimal system of measurement in 1670. mouton based it on the length of one minute of arc of a great circle of the earth (now called a nautical mile, 1852 meters). he also proposed the swing-length of a pendulum with a frequency of one beat per second as the unit of length (about 25 cm). a pendulum beating with this length would have been fairly easy to produce, thus facilitating the widespread distribution of uniform standards. over the years, his work was revised, improved, and extended by a number of french scientists.

the political sponsor of weights and measures reform in the french revolutionary national assembly was the bishop of autun, better known as talleyrand. under his auspices, the french academy appointed several committees to carry out the work of developing a usable system of weights and measures for france. one of the committees recommended a decimalized measurement system based upon a length equal to one ten-millionth of the length of a quadrant of the earth’s meridian (i.e., one ten-millionth of the distance between the equator and the north pole).

it’s previous models   because when i picked that son of a gun’s answer it was wrong look for previous models because they might make it a different letter