Question

Velma is extremely nearsighted, and has difficulty seeing anything which is further away than 1.5 meters from her face if she isn't wearing her glasses. Dexter also wears glasses, which correct his farsightedness; he can only see objects clearly when they are more than 50 cm from his eyes. Assuming that each of them wears glasses which are 1.5 cm from their eyes, and that a person with normal vision has a near point of 25 cm and a far point of infinity, determine:

a. The focal length of Velma's glasses.

b. The focal length of Dexter's glasses.

c. The furthest away that Velma would be able to make out something if she accidentally switched glasses with Dexter.

Answer 1