Question
Asked Dec 6, 2019
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how many photons are there in a 7.00 mJ laser beam of wavelength 785 nm?

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Expert Answer

Step 1

The wavelength is given as 785 nm and the energy of 1 photon having this wavelength is calculated as,

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hc E where, h is Planck's constant (6.626 x 10-34 Joule - sec), c is the speed of light (3 x 108 m/s) and 2 is the wavelength.

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Step 2

Substituting the values,

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he E = 6.626 х 10-34 x3x10° E = 785 х 10-9 E = 2.53 x 10-19 J

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Step 3

Now it is required to calculate the number of...

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2.53 x 10-19 J corresponds to =1 electron 7 x 10-3 J will contain x 7 x 10-3 = 2.76 x 1016 electrons 2.53 x 10-19

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Chemistry

Atomic structure

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