A convex refracting surface has a radius of 12 cm. Light is incident in air (n = 1) and refracted into a medium with an index of refraction of 2. To obtain light with rays parallel to the central axis after refraction a point source should be placed on the axis: 

A. 3 cm from the surface 

B. 6 cm from the surface 

C. 12 cm from the surface 

D. 18 cm from the surface 

E. 24 cm from the surface

A concave spherical surface with radius r separates a medium with index of refraction 2 from air. As an object is moved toward the surface from far away along the central axis, its image: 

A. changes from virtual to real when it is r/2 from the surface 

B. changes from virtual to real when it is 2r from the surface 

C. changes from real to virtual when it is r/2 from the surface 

D. changes from real to virtual when it is 2r from the surface 

E. remains virtual

A parallel beam of monochromatic light in air is incident on a plane glass surface. In the glass, the beam: 

A. remains parallel 

D. undergoes dispersion 

B. becomes diverging 

E. follows a parabolic path 

C. becomes converging

A hollow lens is made of thin glass, as shown. It can be filled with air, water (n = 1.3) or CS₂ (n = 1.6). The lens will diverge a beam of parallel light if it is filled with:

A. air and immersed in air 

B. air and immersed in water 

C. water and immersed in CS2 

D. CS₂ and immersed in water 

E. CS₂ and immersed in CS₂

An object is 2 m in front of a plane mirror. Its image is: 

A. virtual, inverted, and 2 m behind the mirror 

B. virtual, inverted, and 2 m in front of the mirror 

C. virtual, erect, and 2 m in front of the mirror 

D. real, erect, and 2 m behind the mirror 

E. none of the above

A concave refracting surface of a medium with index of refraction n produces a real image no matter where an object is placed outside: 

A. always 

B. only if the index of refraction of the surrounding medium is less than n 

C. only if the index of refraction of the surrounding medium is greater than n 

D. never 

E. none of the above

The image produced by a convex mirror of an erect object in front of the mirror is always: 

A. virtual, erect, and larger than the object 

B. virtual, erect, and smaller than the object 

C. real, erect, and larger than the object 

D. real, erect, and smaller than the object 

E. none of the above

A card marked IAHIO8 is standing upright in front of a plane mirror. Which of the following is NOT true? 

A. The image is virtual

B. The image shifts its position as the observer shifts his position 

C. The image appears as 8OIHAI to a person looking in the mirror 

D. The image is caused mostly by specular rather than diffuse reflection 

E. The image is the same size as the object

A convex spherical surface with radius r separates a medium with index of refraction 2 from air. As an object is moved toward the surface from far away along the central axis, its image: 

A. changes from virtual to real when it is r/2 from the surface 

B. changes from virtual to real when it is r from the surface 

C. changes from real to virtual when it is r/2 from the surface 

D. changes from real to virtual when it is r from the surface 

E. remains real 

An ordinary magnifying glass in front of an erect object produces an image that is: 

A. real and erect 

B. real and inverted 

C. virtual and inverted 

D. virtual and erect 

E. none of these