Compton Scattering Class Exercises AP Physics 1. What is a photon? 2. Is a photon more like a particle or more like a wave? et!s look a little more closely at the photoelectric e""ect# $. A 2%% nm l ight wave is a&sor&e' &y the most 'istant elect ron "rom the n(cl e(s in an al (min(m atom. a) *ow "ast is the electron moving a"terwar'? &) A"ter it a&sor&s the light+ the electron has kinetic energy which means that it also has moment(m. *ow m(ch moment(m 'oes the electron have? c) Is moment(m conserve' when the photon i s a&sor&e' &y the elect ron? Explain ,. *ow m(ch moment(m is carri e' &y a photon o" each o" the "ol lowing wavelengths o" light? a) ,%% nm -violet) &) %% nm -re') c) 12/ nm -(ltraviolet) /. Consi'er a "ree electron that a&sor&s a 12/ nm photon. a) I" the photon!s energy is converte' i nto kinetic energy in the electron+ how "ast is the electron going a"terwar'? &) *ow m(ch moment(m will the moving electron have? Is moment (m conserve' when the photon is a&sor&e'? -0emem&er ,c)
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. We know that moment(m an' energy have to &e conserve' in
every event. *ow is it possi&le to conserve&oth energy an'
moment(m when a photon colli'es3 with a "ree electron?
. *ow wo(l' things change i" the photon was not a&sor&e'
&y the electron+ &(t was scattere' o"" o" it?-0e"lection
an' re"raction are 4(st special types o" scattering.) Conserve
energy an' moment(m.
5. et!s look at a pict(re o" this event an' "ig(re o(thow we
wo(l' write the e6(ations to conserve
energy an' moment(m.
7. Elastic scattering o" 89rays was o&serve'
an' explaine' &y the American physicist Arth(r *.
Compton in 172$. et!s investigate what he"o(n'. :he 'otte' line
on the graph shows
meas(rements o" 89rays that came 'irectly "rom
the so(rce. :he soli' line on the graph shows
meas(rements o" 89rays that were scattere' o"" o" a
graphite &lock. What is 'i""erent a&o(t the 'ata
recor'e' in the two lines?
1%. Why wo(l' it &e &etter to per"orm this experiment
with 89rays instea' o" visi&le light?
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11. A &eam o" x9rays with a photon energy o" 12%% e;
scatters o"" electrons in a metal.
i) What is the wavelength an' "re6(ency o" these waves?
