# Worksheet by keralaguest

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```									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 anti-reflective
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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