The figure illustrates a number of optical lenses made of glass with index of refraction n. 

If used in eyeglasses, that type of lens would help for: (choose far sighted or near sighted)
a. W, for a .... person.
b. Y, for a .... person.
c. X, for a .... person.

 How far from a concave mirror (radius 23.4 cm) must an object be placed if its image is to be at infinity?

 

3. The image of a distant tree is virtual and very small when viewed in a curved mirror. The image appears to be 14.1 cm behind the mirror. What is its radius of curvature? (Use positive for concave and negative for convex).

 

4. The figure illustrates a number of optical lenses made of glass with index of refraction n. An equation from which the focal length of each lens in air can be calculated is:
1/f = ( n-1 )( ± 1/r1 ± 1/r2 )
where r1 and r2 are the magnitudes of the radii of curvature of the lens surfaces.

Indicate the signs which are appropriate for the 1/r1 and 1/r2 terms in that equation:

a. For lens Z, the respective signs of 1/r1 and of 1/r2 are ....
b. For lens W, the respective signs of 1/r1 and of 1/r2 are ....
c. For lens Y, the respective signs of 1/r1 and of 1/r2 are ....

 

5. A dentist wants a small mirror that, when 2.12 cm from a tooth, will produce a 4.62x upright image. What is the mirror's radius of curvature?

 

6. The magnification of a convex mirror is +0.600x for objects 2.00 m from the mirror. What is the focal length of this mirror?

 

7. The refractive index of a transparent material can be determined by measuring the critical angle when the solid is in air. If θ_c= 41.7^o, what is the index of refraction of the material?

 

N D X r2 r2 r1 1 r2 f r1 W r1 r2