CHAPTER 19 Study Guide
19.1 Mirrors
Key Concepts
The law of reflection states that the angle of reflection is equal to the angle of incidence.
A plane mirror always produces a virtual image.
Concave mirrors can form either real or virtual images.
Convex mirrors always cause light rays to spread out and can only form virtual images.
Vocabulary
ray diagram, p. 570
angle of incidence, p. 570
angle of reflection, p. 570
plane mirror, p. 571
virtual image, p. 571
concave mirror, p. 572
focal point, p. 572
real image, p. 572
convex mirror, p. 573
19.2 Lenses
Key Concepts
When light enters a new medium at an angle, the change in speed causes the light to bend, or refract.
Concave lenses always cause light rays to spread out and can only form virtual images.
Convex lenses can form either real or virtual images.
Materials that have small critical angles of refraction are likely to cause most of the light entering them to be totally internally reflected.
Vocabulary
index of refraction, p. 575
lens, p. 576
concave lens, p. 576
convex lens, p. 576
critical angle, p. 578
total internal reflection, p. 578
19.3 Optical Instruments
Key Concepts
There are two main types of telescopes, reflecting telescopes and refracting telescopes.
Light rays enter a camera through an opening, are focused by the opening or lens, and form an image that is recorded on film or by a sensor.
The compound microscope uses two convex lenses to magnify small objects.
Vocabulary
telescope, p. 580
reflecting telescope, p. 581
refracting telescope, p. 581
camera, p. 582
microscope, p. 584
19.4 The Eye and Vision
Key Concepts
The main parts of the eye are the cornea, the pupil and iris, the lens, and the retina.
Some common vision problems are nearsightedness, farsightedness, and astigmatism.
Vocabulary
cornea, p. 588
pupil, p. 589
iris, p. 589
retina, p. 589
rods, p. 589
cones, p. 589
nearsightedness, p. 590
farsightedness, p. 592
astigmatism, p. 592
Thinking Visually
Concept Map Use the information from the chapter to complete the concept map below.
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