# 15 Homework Problems

- Identify the portion of the eye responsible for most of the focusing of light.
- What is the purpose of the iris?
- In geometric optics, we do analyses using similar triangles. This problem is here to help you practice working on these again.
- Look at this map and determine the angle.
- For this set of intersecting lines, use the following information to find the missing values.
- Indicate where the outgoing ray from a mirror intersects the dotted line.
- What is the speed of light in water? In glycerine? The indices of refraction for water is 1.333 and for glycerine is 1.473.
- Calculate the index of refraction for a medium in which the speed of light is 1.416×108 m/s.
- Consider two materials. When light passes through the space between the two materials at 0°<θ<90°, there is no change in the direction of the propagation of the light. What can you infer about the two materials?
- Which of the properties of a light ray change as it goes from glass to vacuum?
- What are the wavelengths of visible light in crown glass?
- Suppose you have an unknown clear substance immersed in water, and you wish to identify it by finding its index of refraction. You arrange to have a beam of light enter it at an angle of 48.6∘, and you observe the angle of refraction to be 32.4∘. What is the index of refraction of the substance? Water has an index of refraction equal to 1.333.
- A beam of white light goes from air into water at an incident angle of 83.0∘. At what angles are the red 660 nm and violet 410 nm parts of the light refracted? Red light in water has an index of refraction equal to 1.331 and that of violet light is 1.342.
- Given that the angle between the ray in the water and the perpendicular to the water is 28.3
^{∘}, and using information in the figure above, find the height of the instructor’s head above the water. Water has an index of refraction equal to 1.333. - Sign conventions for object and image distances: objects and images on opposite sides of the optical element.
- Sign conventions for object and image distances: objects and images on same side of the optical element.
- What characterizes an object with a negative magnification?
- Calculating magnification of a gemstone.
- Characterizing lenses.
- Diopters to focal length.
- Focal length to diopters.
- Focal lengths of mirrors.
- Ray diagrams: converging lenses.
- Ray diagrams: diverging lenses.
- Ray diagrams: concave mirrors.
- Ray diagrams: convex mirrors.