Question

A 193nm-wavelength UV laser for eye surgery emits a 0.500mJ pulse. (a) How many photons does the light pulse contain?

Answer 1

Using the equation E = hc/λ we can find out how much energy a single photon of wavelength 193 nm has. E = Planck Constant * Speed of Light/193 nm

Answer 2

The number of photons is 4.8x10^14

Step-by-step explanation:

The frequency of wave is equal to:

`f=(c)/(l)`

where c is the speed of light, l is the wavelength of wave. Replacing values:

`f=(3x10^(8) )/(193x10^(9) ) =1.5x10^(15) Hz`

The energy of the proton is:

`E=hf`

where h is the Planck´s constant. Replacing

`E=6.626x10^(-34)*1.5x10^(5)=1.03x10^(-18) J`

The number of photons is:

`n=(E1)/(E)`

where E1 is the energy of photon. Replacing:

`n=(0.5x10^(-3) )/(1.03x10^(-18) )=4.8x10^(14)`