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3)#he reason we $et the ima$e shown when the knife is on
midfocus has to do with the
wa%elen$ths of the li$ht plus the $eometry of the li$ht
&locked. #he knife ed$e is &lockin$ the
li$ht &efore it hits the focus point' meanin$ that if the
li$ht is &locked on the left' the ima$e on
the ri$ht will &e dark. (owe%er' here we o&ser%e that
the left outer shell is dark and the ri$htinner part is also dark.
#he $eometry at the midfocus ends up &lockin$ the outer ri$ht
shell' and
lea%in$ the rest of that semicircle $o throu$h. #he left inner
part is clipped &y the knife ed$e'&ut there is some li$ht
that mana$es to make it throu$h at the outer shell. *ne will &e
from one
mirror and the other will &e from the other mirror.
+),n the Foucault test' the shadowed section re%erses as the
knife ed$e mo%es across the path
lon$itudinally &ecause if the knife is &efore focus and
&lockin$ the left' due to the $eometry of
the li$ht path' the li$ht on the ima$e will &e &locked
on the ri$ht' &ut as the knife mo%es and&locks the ri$ht
side of the li$ht' the ima$e experiences a shadow to the left once
a$ain due to
$eometry. ,-ll draw a picture demonstratin$ the first one once
this is printed.
)
)
/chlieren photo$raphy is used for ima$in$ the flow of fluids.
#he process works &y ha%in$ a acollimated source illuminate a
tar$et or &ehind the tar$et). /ince air flow causes density
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$radients' the refracti%e index is %aried' causin$ distortions
on the collimated li$ht. #his allows
for the flow to &e ima$ed usin$ shadow$raph.
)
/ome applications of /chlieren photo$raphy would &e the
study of shockwa%es' studyin$ the
chan$es of pressure due to heat in $as)' and detectin$ $as
leaks.
!)
2n 2 %ariant &ein$ fired left) and a supersonic F1
ri$ht)
2nd here-s an F1! &ecause 4arines5 that-s why6
