I
realize that I made a ridiculously stupid mistake on the physics test today.
Rah. How frustrating. >_< And more sad news (or not, haha): this will be
my last physics blog post. Aww... :[
I
don’t really know how to relate quantum physics to everyday life, though,
except by likening the photoelectric effect to photosynthesis, which is quite important in our lives, I'd say (biology and
physics in one post?!? o_O). And of course I don't really know anything about photosynthesis anymore because I don’t
even remember what I (should have) learned yesterday, let alone information from 9th
grade biology. So let’s get cracking.
The
photoelectric effect is the ejection of electrons due to light striking a
material. An increase in light intensity results in more electrons being
released because more intense light => more photons => more electrons
emitted. However, the light must be greater than a certain frequency, otherwise
no electrons will be emitted at all, regardless of the intensity, since low
frequency => less energetic photons => not enough energy to free
electrons. An equation we can relate to the photoelectric effect is E = KE + ø,
where E is the energy of the photon (also equal to hf), KE is the kinetic
energy of the released electrons (0.5mv2), and ø is the work
function of the material (the minimum amount of energy needed for an electron
to be ejected from it).
Photosynthesis
is like the photoelectric effect because in both cases, light striking a
material results in the emission of electrons. When sunlight shines on a plant,
chlorophyll molecules absorb it and they become excited, releasing electrons.
(Some complicated processes occur here to transport electrons...). And by the end, the electrons have been
converted to ATP, and photosynthesis has successfully converted light into
sugar. :]