- #1

songoku

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## Homework Statement

1. Peter cannot see distinctly objects closer than 40 cm from the eye. Find the power of lens that enable him to see objects at distinct vision

2. A man has near point of 50 cm and a far point of 200 cm.

a. What kind of glass should he used to see normally?

b. What are the power of the lenses?

3. A lens of 4-cm focal length is used as a magnifying glass. Where the object must be placed to produce a virtual image at distinct vision from the lens and what is the magnification?

4. A microscope has an objective lens of 9 mm focal length and an eyepiece of 5-cm focal length. A bug 1/2 mm long is placed 1 cm from the objective lens. Locate the image

## Homework Equations

1/f = 1/do + 1/di where do = distance of object and di = distance of image

P = 100/f

## The Attempt at a Solution

1. What is the meaning of "distinct vision"? At first, I thought it meant "very far" but it would seem weird because it will be unclear whether peter is farsighted or nearsighted. Or "distinct vision" means normal near point = 25 cm?

2. a. Bifocal lens

b. How to find the power? Is it correct to find the power of the lenses separately, one using near point and the other using far point? If it is so, the answer will be two values for power of the lenses?

3. Again, "distinct vision". If it means "very far", the object must be placed at focus and the magnification is infinity?

4. The question is asking about distance of image from eye-piece lens, right? I am able to find the distance of image from objective lens but how to find the distance of object for eye-piece lens?

Thanks