91影视

Energy of photons of light is defined as the energy carried by the photons and it is directly proportional to the light鈥檚 frequency.

The energy of a single photon is expressed as, $E=fh$where, $E$is Energy of a single photon, $f$is frequency of light and $6.626脳{10}^{-34}$Js is Planck鈥檚 constant.

Intensity of light is defined as power per unit area per unit time.

The intensity of sunlight falling on Earth鈥檚 surface is the energy received by the Earth鈥檚 curved surface area in one second.

Frequency of green light is$f=550脳{10}^{12}Hz.$

Substitute value of frequency and Planck鈥檚 constant into formula of energy of single photon.

$$\begin{gathered} E=550脳{10}^{12}脳6.626脳{10}^{-34} \\ =3.643脳{10}^{-19}\mathrm{J} \end{gathered}$$

Therefore, the approximate energy of the photons of green light is$3.643脳{10}^{-19}$ .

Given that, the intensity of sunlight above the Earth鈥檚 atmosphere is about $1400W$per square meter.

The formula for intensity of light is, $l=\frac{NE}{tA}$where $l$is intensity of light, N is number of photons, E is energy of single photon, t is time duration and A is area of the surface.

The number of photons falling on unit area in unit time is$N=\frac{ltA}{E}$

Substitute the values into the obtained formula to obtain the required number of photon.

$$\begin{gathered} \mathrm{N}=\frac{1400\mathrm{J}/{\mathrm{sm}}^2脳1\mathrm{s}脳1{\mathrm{m}}^2}{3.643脳{10}^{-19}\mathrm{J}} \\ =3.84脳{10}^{21} \end{gathered}$$

Thus, the approximate energy of the photons of green light is$3.643脳{10}^{-19}\mathrm{J}$ and$3.84脳{10}^{21}$ photons per second strike an area of one square meter.