An LED emits a light beam with a power of 10 mW. The wavelength of the light is 420 nm. How many 420nm photons are emitted per sec.?
E=hc/lamda is 2.95E-9
P/E= Photons emitted per sec.
The Attempt at a Solution
2.95E-11 is wrong.
2.1E16 photons per/sec. is the answer