# Worksheet: Thin Lenses

In this worksheet, we will practice applying the thin lens formula to lenses of different radii of curvature and refractive indices to find their foci.

**Q3: **

A slide projector uses a mm-focal length lens to project images onto a screen.

How far away is the screen if a slide is placed 103 mm from the lens and produces a sharp image on the screen?

If the dimensions of the slide are 24.0 cm by 36.0 mm, what are the dimensions of the image on the screen?

- A
- B
- C
- D
- E

**Q5: **

A camera with a lens of focal length 50.0 mm is being used to photograph a person standing 3.00 m away.

How far from the camera’s lens is its photosensor?

What is the maximum height of a person whose image can be formed onto a section of the photosensor that is 36.0 mm high using this camera at this distance?

**Q10: **

An object of height 3.0 cm is placed at 25 cm in front of a diverging lens of focal length 20 cm. Behind the diverging lens, there is a converging lens of focal length 20 cm. The distance between the lenses is 5.0 cm.

How far to the right of the converging lens is the final image formed?

What is the height of the final image?

**Q14: **

A camera lens used for taking close-up photographs has a focal length of 22.0 mm. The farthest the lens can be placed from the camera’s photosensor is 33.0 mm. At distances from the lens less than a distance , it is not possible to produce an image that is in focus.

Find .

What magnification is produced at ?

**Q16: **

Two convex lenses of focal lengths 25 cm and 13 cm, respectively, are placed 60 cm apart, with the lens of longer focal length on the right. An object of height 2.5 cm is placed equidistantly between the lenses and observed through each lens from the left and from the right.

What is the distance between the right-hand lens and the object image produced by it?

What is the distance between the left-hand lens and the object image produced by it?