Calculate the number of photons that would be contained in a laserpulse with a wavelength of 287 nm that contained 4.35 mJ of energy. Plank's constant is 6.626 x 10-34 J•s. 2.87 x 10-7 photons 3.00 x 108 photons 1.59 x 10-16 photons 6.28 x 1015 photons 7.41 x 1012 photons

3.46 ⋅ 10 − 19 J

Explanation:

The energy of a photon is proportional to its frequency,

why do the isotopes of a particular element behave differently in nuclear reactions but the same in chemical reactions? chemical reactions involve changes to electrons in an atom; isotopes do not differ in electrons, and so they react the same way during chemical changes.