SAT Physics Practice Test: Optics

1. What is the wavelength of an X-ray whose frequency is 1.0 x 10¹⁸Hz?

(A) 3.3 x 10^-11 m
(B) 3.0 x 10^-10 m
(C) 3.3 x lQ^-9 m
(D) 3.0 x 10^-8 m
(E) 3.0 x lO²⁶ m

2. In Young’s double-slit interference experiment, what is the difference in path length of the light waves from the two slits at the center of the first bright fringe above the central maximum?

(A) 0
(B) λ/4
(C) λ/2
(D) λ
(E) 3λ/2

3. A beam of light in air is incident upon the smooth surface of a piece of flint glass, as shown

If the reflected beam and refracted beam are perpendicular to each other, what is the index of refraction of the glass?

(A) 1/2
(B) 0.5√3
(C) √3
(D) 2
(E) 2√3

4, When green light (wavelength = 500 nm in air) travels through diamond (refractive index = 2.4), what is its wavelength?

(A) 208 nm
(B) 357 nm
(C) 500 nm
(D) 700 nm
(E) 1,200 nm

5. A beam of light traveling in medium 1 strikes the interface to another transparent medium, medium 2. If the speed of light is less in medium 2 than in medium 1, the beam will

(A) refract toward the normal
(B) refract away from the normal
(C) undergo total internal reflection
(D) have an angle of reflection smaller than the angle of incidence
(E) have an angle of reflection greater than the angle of incidence

6. If a clear liquid has a refractive index of 1.45 and a transparent solid has an index of 2.90 then, for total internal reflection to occur at the interface between these two media, which of the fallowing must be true?

at an angle
incident beam 　　　　of incidence
originates in　　　　　greater than

(A) the solid　 　　　　30°
(B) the liquid　　　 　　30°
(C) the solid 　　　　　60°
(D) the liquid　　　　　60°
(E) Total internal reflection cannot occur.

7. An object is placed 60 cm in front of a concave spherical mirror whose focal length is 40 cm. Which of the following best describes the image?

Nature of imaee　　 Distance from mirror
(A) Virtual　　　　 24 cm
(B) Real　　　　　　24 cm
(C) Virtual 　　　　120 cm
(D) Real　　　　　　120 cm
(E) Real　　　　　　240 cm

8. An object is placed 60 cm from a spherical convex mirror. If the mirror forms a virtual image 20 cm from the mirror, what’s the magnitude of the mirror’s radius of curvature?

(A) 7.5 cm
(B) 15 cm
(C) 30 cm
(D) 60 cm
(E) 120 cm

9. The image created by a converging lens is projected onto a screen that’s 60 cm from the lens. If the height of the image is 1/4 the height of the object,
what’s the focal length of the lens?

(A) 36 cm
(B) 45 cm
(C) 48 cm
(D) 72 cm
(E) 80 cm

10. Which of the following is true concerning a biconcave lens?

(A) Its focal length is positive.
(B) It cannot form real images.
(C) It cannot form virtual images.
(D) It can magnify objects.
(E) None of the above