Refraction and Lenses
Practice Test
1.
Why are bigger lenses better for observing dim objects?
a.
they have better curvatures
b.
they reduce spherical aberration
c.
they collect more light
d.
they refract light less
Hint
2.
The focal length of a concave lens is __________.
a.
positive
b.
magnified
c.
negative
d.
reduced
Hint
3.
Farsightedness can be corrected with a __________.
a.
convex lens
b.
plane lens
c.
concave lens
d.
parabolic lens
Hint
4.
In nearsightedness, the image is focused __________.
a.
in front of the eye
b.
beyond the retina
c.
directly on the retina
d.
in front of the retina
Hint
5.
Because of refraction, the Sun actually sets __________ we see it disappear.
a.
after
b.
hours before
c.
before
d.
at the same time as
Hint
6.
Why would it be impossible to have optical fibers filled with a vacuum?
a.
there is nothing for light to travel through
b.
because a vacuum is too optically dense
c.
there is nothing less optically dense than a vacuum
d.
because optical fibers must use glass
Hint
