Type your question here A laser pulse with wavelength 555 mm

Type your question here

-A laser pulse with wavelength 555 mm<?xml:namespace prefix = v ns = \"urn:schemas-microsoft-com:vml\" /> <?xml:namespace prefix = o ns = \"urn:schemas-microsoft-com:office:office\" /> contains 4.40 m.J of energy

How many photons are in the laser pulse?

Solution

let the number of photons be x.

so,

energy of a photon=hc/lambda

=6.636*10^-34*3*10^8/0.555

so,

n*6.636*10^-34*3*10^8/0.555=4.4*10^-3

or n=1.2266*10^22 photons