A.Calculate the frequency of light that has a wavelength of 340nm Show how you d

Question

A.Calculate the frequency of light that has a wavelength of 340nm

Show how you did it please :)

The rays of the Sun that cause tanning and burning are in the ultraviolet portion of the electromagnetic spectrum. These rays are categorized by wavelength: So-called UV-A radiation has wavelengths in the range of 320-380 nm - nm photons. To kJ/mol Show how you did it please :) nm . A.Calculate the frequency of light that has a wavelength of 340nm B.Calculate the energy of a mole of 340 ? nm , whereas UV-B radiation has wavelengths in the range of 290-320 nm

Explanation / Answer

Part (a): The frequency f is inversely proportional to the wavelength w; they're related
by the formula f * w = c, where c is the speed of light, 2.998 * 10**8 meters per sec.
Then f = c/w, or 2.998 * 10**8 / 3.5 * 10**-7 = 8.565 * 10**14 waves per sec. or Hz.
Part (b): Planck's equation gives the energy E per photon as E = hf, where f is the
frequency and h is Planck's constant, 6.625 * 10**-34 joule-second. So the energy
of one photon is (6.625 * 10**-34)(8.565 * 10**14) = 5.674 * 10**-19 joule. One mole
of photons is Avogadro's number (6.023 * 10**23) of photons, we multiply E for one
photon by 6.023 * 10**23 to get: (5.674 * 10**-19)(6.023 * 10**23) = 3.417 * 10**5
joules, or 341.7 kilojoules per mole of photons.

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