An argon ion laser puts out 5.0 w of continuous power at a wavelength of 532 nm. the diameter of the laser beam is 5.5 mm. if the laser is pointed toward a pinhole with a diameter of 1.2 mm, how many photons travel through the pinhole per second? assume that the light intensity is equally distributed throughout the entire cross-sectional area of the beam. (1 w = 1 j/s)

Number of photons travel through pin hole=

Explanation:

First we will calculate the energy of single photon using below formula:

Where :

h is plank's constant with value

c is the speed of light whch is

λ is the wave length = 532nm

E=J

Number of photons emitted per second:

Number of photons emitted per second=

=

Where:

A-hole is area of hole

A-beam is area of beam

d-hole is diameter of hole

d-beam is diameter if beam

=

=

=

Number of photons travel through pin hole=

Number of photons travel through pin hole=

at positions a, g kinetic energy is maximum.

at position d, potential energy is maximum.