MR. SURRETTE
VAN NUYS HIGH SCHOOL
CHAPTER 16: OPTICS
MIRROR DIAGRAM HANDOUT
RAY DIAGRAMS FOR MIRRORS
1. The first ray is drawn from the top of the object (the object is drawn as an arrow). The ray is
parallel to the optical axis and is reflected back through the focal point, F.
2. The second ray is drawn from the top of the object to the vertex (center) of the mirror and is
reflected with the angle of incidence equal to the angle of reflection.
3. The third ray is drawn from the top of the object through the center of curvature, C, which is
reflected back on itself.
MIRROR DIAGRAM EXAMPLE
RULES FOR MIRROR DIAGRAMS
1. If O > 2F, the image is inverted, smaller, and located between F and 2F.
2. If O = 2F (at C), the image is inverted, the same size as the object, i.e. the distances of both
the object and image to the mirror are equal.
3. If 2F < O < F, the image is inverted, larger than the object, and located > 2F.
VIRTUAL IMAGES
A virtual image is formed because the reflected rays diverge from the surface of the mirror. The
virtual image is upright, enlarged, and behind the mirror. Virtual images are never inverted.
VIRTUAL IMAGE EXAMPLE
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PHYSICS
MR. SURRETTE
VAN NUYS HIGH SCHOOL
CHAPTER 16: OPTICS
LENS DIAGRAM HANDOUT
RAY DIAGRAMS FOR THIN LENSES
The following three rays form the ray diagram for a thin lens.
1. The first ray is drawn parallel to the optic axis. After being refracted by the lens, this ray
passes through (or appears to come from) one of the focal points.
2. The second ray is drawn through the center of the lens. This ray continues in a straight line.
3. The third ray is drawn through the focal point F, and emerges from the lens parallel to the
optic axis.
CONVERGING LENS EXAMPLES
DIVERGING LENS EXAMPLE
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PHYSICS
MR. SURRETTE
VAN NUYS HIGH SCHOOL
CHAPTER 16: OPTICS
WAVE OPTICS HANDOUT
YOUNG’S DOUBLE-SLIT APPARATUS
xm = mL / d
dsin = m
INTERFERENCE IN THIN FILMS
2nt = (m + ½)
BREWSTER’S LAW
n = tanp
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PHYSICS
MR. SURRETTE
VAN NUYS HIGH SCHOOL
CHAPTER 16: OPTICS
WORKSHEET
(Equations: M = - si/so, 1/si + 1/so = 1/f, 1/FT = (1/Fi), f = R/2, PT = Pi xm = mL / d,
2nt = (m + ½ ), n = tanp)
1. Which of the following best describes the image of a concave mirror when the object is at a
distance greater than twice the focal point from the mirror?
(A) virtual, erect; and magnification greater than one
(B) virtual, inverted; and magnification greater than one
(C) real, inverted; and magnification less than one
(D) virtual, erect; and magnification less than one
(E) real, inverted; and magnification greater than one
2. If a man’s face is 25.0 cm in front of a concave shaving mirror creating an erect image 2.25
times as large as the object, what is the object’s focal length? [ANS: 45 cm]
3. An object is placed at a distance of 35.0 cm from a thin lens along an axis. If a virtual image
forms at a distance of 70.0 cm from the lens, on the same side of the object, what is the focal
length of the lens?
[ANS: 70 cm]
4. Two thin lenses of focal lengths 15.0 and 20.0 cm, respectively, are placed in contact so that
their optic axes coincide. What is the focal length of the two in combination? [ANS: 8.6 cm]
Questions 5 - 7. A concave spherical mirror has a radius of curvature of 24 cm. An object is
placed 36 cm from the mirror’s vertex.
5. What is the focal length of this mirror?
]ANS: 12 cm]
6. Sketch a ray diagram.
7. Calculate the image distance and describe the image.
[ANS: 18 cm (inverted)]
8. A concave spherical mirror has a radius of curvature of 30 cm. An object is placed 12 cm
from the mirror’s vertex. Sketch a ray diagram.
9. A double-convex lens has a 20 cm radius of curvature for both sides. An object is placed 7
cm from the mirror’s vertex on the left-hand side. Sketch a ray diagram.
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PHYSICS
MR. SURRETTE
VAN NUYS HIGH SCHOOL
10. A Young’s double slit apparatus has a slit separation of 4.75 x 10-5 m on which a
monochromatic light beam is directed. The resultant bright fringes on a screen 1.30 m away are
separated by 1.75 x 10-2 m. What is the wavelength of the beam? [ANS: 639 nm]
11. Constructive interference occurs when light of wavelength 565 nm shines on soap bubble
film (n = 1.46). What is the minimum thickness of the film? [ANS: 96.7 nm]
12. A beam of unpolarized light strikes a flat piece of glass at an incidence angle of 49.5o. If the
reflected beam is completely polarized, what is the glass’ index of refraction? [ANS: 1.17]
13. In a Young’s double-slit experiment, by what factor is the distance between adjacent light
and dark fringes changed when the wavelength of the source is tripled? [ANS: 3x]
14. A possible means for making an airplane radar-invisible is to coat the plane with an antireflective polymer. If radar waves have a wavelength of 2.25 cm and the index of refraction of
the polymer is n = 1.62, how thick would the coating be? [ANS: 3.47 mm]
Questions 15 - 16. Light in the form of plane waves of a single wavelength are incident on two
parallel slits. A viewing screen is a distance D from the slits. A point P on the screen is a
distance r1 from one slit and r2 from the other.
15. If the difference in the distances (r2 – r1) is 1.5 wavelengths (3/2) what would be observed
at P?
16. If the difference in the distances (r2 – r1) is 2.0 wavelengths (2) what would be observed at
P?
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PHYSICS