An elderly sailor is shipwrecked on a desert island, but manages to save his eyeglasses. The lens for one eye has a power of +1.20 diopters, and the other lens has a power of +9.00 diopters. (a) What is the magnifying power of the telescope he can construct with these lenses? (b) How far apart are the lenses when the telescope is adjusted for minimum eyestrain?

A near-sighted man can only focus on distances of dfar = 5.66 m or closer. What power lenses does he need in his glasses for distance vision? Your answer should be in diopters (m-1).

What is a megapixel in a digital camera?(a) A large spot on the detector where the image isfocused.(b) A special kind of lens that gives a sharper image.(c) A number related to how many photographs thecamera can store.(d) A million light-sensitive spots on the detector.(e) A number related to how fast the camera can takepictures.

An amateur astronomer wants to build a telescope with a diffraction limit that will allow him to see if there are people on the moons of Jupiter.  (a) What diameter mirror is needed to be able to see 1.00 m detail on a Jovian Moon at a distance of 7.50×108 km from Earth? The wavelength of light averages 600 nm.  (b) What is unreasonable about this result? (c) Which assumptions are unreasonable or inconsistent?

The angular magnification of an astronomical telescope in normal adjustment is 36, and the diameter of the objective lens is 72mm. (Notice that this is the same configuration as a beam expander, see figure below which is NOT to scale. a. What is the minimum diameter of the eyepiece required to collect all the light entering the objective lens from a distant point source on the axis of the instrument? b. In order to use the thin lens approximation, the radius of curvature of the lens should be larger than the diameter of the lens itself. For a radius of curvature of 720mm for both sides of the objective lens (one is negative, one is positive), and an index of refraction of the objective glass of 1.5, what is the focal length of the Objective Lens?c. What is the focal length of the eyepiece given the focal length of the objective lens? d. What is the minimum length of the telescope? (i.e. the total distance between the eyepiece and the objective lenses).

What is the power of the eye in D when viewing an object 29.6 cm away? (Assume the lens-to-retina distance is 2.00 cm.)