Saved Bookmarks
| 1. |
Monochromatic light of wavelength 632.8 nm is produced by a helium-neon laser. The power emitted is 9.42mW. How many photons per second, on the average, arrive at a target irradiated by this beam ? (Assume the beam to have uniform cross-section which is less than the target area), |
|
Answer» <P> Solution :Here, `lamda=632.8nm=632.8xx10^(-9)m`,`P=9.42mW=9.42xx10^(-3)W` Number (n) of photons falling per second on the TARGET is `n=(P)/(E)=(9.42xx10^(-3))/(3.14xx10^(-19))=3XX10^(16)` photons/sec |
|