You are hanging out with your friend Liz you decided to warm up some snacks in t

Question

You are hanging out with your friend Liz you decided to warm up some snacks in the microwave. Liz then tells you she doesn't microwave her food because she read in a magazine that microwave radiation is even more dangerous than being exposed to UV light because of the high levels of energy and microwave radiation. You disagree with your friend and determine the energy of both types of electromagnetic radiation to prove her wrong. Assume that microwaves have a frequency of approximately 2.5 x 10^9 Hz and that UV light has a frequency of approximately 8.0 x 10^15 Hz.

a) Could you tell if Liz is wrong without any mathematical process, given only the frequencies above?

b) Calculate the energy of one mole of photons of each type.

Explanation / Answer

a) The greater is the value of frequency, larger will penetration capability due to smaller wavelength. Thus we can conclude microwave are safer than UV light, due to smaller frequency.

b) E = h

E= energy of one photon

h= Plank's constant = 6.626 * 10-34 Js

= frequency in Hz

For microwave

= 2.5 * 109

E = (6.626 * 10-34 ) *( 2.5 * 109)

= 1.66 * 10-24 J

E (enery of one mole of photon ) = Avagadro no * energy of one photon

= 6.022 * 1023 *  1.66 * 10-24 = 0.999 J

For UV light

= 8.0 * 1015

E = (6.626 * 10-34 ) *( 8.0 * 1015)

= 5.3 * 10-18 J

E (enery of one mole of photon ) = Avagadro no * energy of one photon

= 6.022 * 1023 *  5.3 * 10-18   = 3.12 * 10-6 J

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