Answer:
[tex]n=2.59\times 10^{16}[/tex] photons
Explanation:
[tex]E=n\times \frac{h\times c}{\lambda}[/tex]
Where,
n is the number of photons
h is Plank's constant having value [tex]6.626\times 10^{-34}\ Js[/tex]
c is the speed of light having value [tex]3\times 10^8\ m/s[/tex]
[tex]\lambda[/tex] is the wavelength of the light
Given that, wavelength = 514 nm = [tex]514\times 10^{-9}\ m[/tex]
Energy = 10.0 mJ = 0.01 J ( 1 mJ = 0.001 J )
Applying the values as:-
[tex]0.01=n\times \frac{6.626\times 10^{-34}\times 3\times 10^8}{514\times 10^{-9}}[/tex]
[tex]\frac{19.878n}{10^{17}\times \:514}=0.01[/tex]
[tex]n=2.59\times 10^{16}[/tex] photons