# ap chem

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How do you set this problem up?

A laser emits at a wavelength 987 nm. all of its output energy is absorbed in a detector that measures a total energy of .52 joules over a period of 52 seconds. how many photons per second are being emitted by the laser?

• ap chem -

E= (hc)/lambda.
You know h, c, and lambda (987 x 10^-9 m), so E will be the energy in joules per photon. Use that to calculate # photons per second.

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