Question

Argon-fluoride excimer lasers are now commonly used in corrective eye surgery. The short, intense pulses of light generated by these lasers are able to cleanly ablate microscopic layers of corneal tissue, effectively reshaping the lens with little or no trauma to the rest of the eye. Calculate the energy delivered to the cornea per laser pulse(in J), if one pulse from an argon-fluoride excimer laser contains 2.5*1016photons, each with a wavelength of 193 nm. (1 nm = 10-9m)A. 1.3*10-40 JB. 1.0*10-27JC. 1.0*10-18JD. 6.2*105JE. 2.6*10-2J

Answer 1

Answer:

Energy, $E=2.6\times 10^{-2}\ J$

Explanation:

It is given that,

Number of photons, $n=2.5\times 10^{16}\ photons$

Wavelength, $\lambda=193\ nm=193\times 10^{-9}\ m$

Let E is the energy delivered to the cornea per laser pulse. The energy of photon is terms of number of photon is given by :

$E=\dfrac{nhc}{\lambda}$

Where

h is Planck's constant

c is the speed of light

$E=\dfrac{2.5\times 10^{16}\times 6.67\times 10^{-34}\times 3\times 10^8}{193\times 10^{-9}}$

E = 0.0259 J

or

$E=2.6\times 10^{-2}\ J$

So, the energy delivered to the cornea per laser pulse is $2.6\times 10^{-2}\ J$. Hence, this is the required solution.