Question

Myrtle is about to put in a contact lens. She looks at her own pupil, up close in a (flat) mirror. Her (spherical) eyeball is 2.0cm in diameter; her (circular) pupil is 0.5mm in diameter. Her pupil is 6cm from the mirror surface. She focuses her eye such that she sees her own pupil perfectly.

A) The image of her own pupil ends up on her retina. What is the physical size of the imaged pupil?

B) What is the effective focal length of her eye (while she is looking at her own pupil)?

C) Make a ray-tracing diagram, showing how the pupil is focused onto the retina. For the object, use the effective image of the pupil in the mirror. Make an additional diagram showing the actual path of light, from the actual pupil, bouncing off the mirror.

D) Her contact lens prescription is -3.0 D. After she puts in her lens, but before she refocuses her eye, at what distance will objects now appear to be in focus?

Answer 1