Question

Monochromatic light of wavelength 667 nm is produced by
a helium neon laser. The power emitted is 9 mW. The
number of photons arriving per sec. On the average at a
target irradiated by this beam is.
(1) 3 x 10^16
(2) 9 x 10^15
(3) 3 x 10^19
(4) 9 x 10^17​

Answer 1

Answer:

Hey Buddy here's ur answer

Answer 2

Answer:

3*10^16

Explanation:

the formula to be used is

n=power*wavelength/hc

now we know the power

p=9mw in standard unit it will be 9*10^-3

wavelength is 667nm

and the hc that is 6.626*10^-34*3*10^8=20*10^-26

putting this terms in the formula

=

9*10^-3*667 / 20*10^-26

6003*10-3/ 20*10^-26

then dividing 20 to this

300.15*10^23

30015*10^21

according the option we have to make the answer

3=10^21/10000

3*10^-16