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A

Anonymous

Nov 26, 2024

A laser pulse with wavelength 505nm contains 4.85mJ of energy.?

A laser pulse with a wavelength of 505 nm emits 4.85 mJ of energy. How many photons are contained within this laser pulse?

3 Answers

A
Anonymous

Dec 14, 2024

1 photon will have an energy of hc/lambda = (6.63 x 10^-34Js x 3 x 10^8m/s)/505 x 10^-9m =

3.94 x 10^-19J

Therefore the No. of photons that have a total energy of 4.85mJ =

(4.85 x 10^-3)/(3.94 x 10^-19) = 1.231 x 10^16 photons

IF the wavelength of the laser pulse is 505nm, the energy possessed by a single photon will be given by {hc/wavelength}, where h=Planck’s Constant= 6.62 x 10 power -34 Js, c=Speed of Light = 3 x 10 power 8 m/s. And the wavelength is given. Substitute in the Planck’s equation and find out the energy of a single photon (lets say it to be x J). Now u have the value for the whole pulse. Divide the value (4.85 MJ) with the energy of the single photon and calculate the number of photons!

P.S. The energy of the laser pulse cannot be such a small value (mJ=milli Joule). Check out the question properly…It has to be MJ=Mega Joule. Milli is 10 power -3 and Mega is 10 power 6.

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