Question

A 10-cm tall object is placed 40 cm away from a lens that has a focal length of +8 cm.

(a) What kind of lens is this?

(b) Draw a ray diagram

(c) Calculate image distance and height

(I got a Di of 10 cm and a H of -2.5 but I can't match that with the diagram)

(d) If you moved the lens a little to the right, the image would
[ ] move to the right [ ] move to the left [ ] not move
and [ ] get taller [ ] get shorter [ ] stay the same size

(e) Now, you immerse the object – lens combination in a liquid that has an index of
refraction larger than that of the lens material (we started with the usual situation of air surrounding
the lens). What happens?
[ ] Nothing changes – it’s all the same as above [ ] No image is formed
[ ] The image is on the same side of the lens as before, but in a different place
[ ] The image is on the opposite side of the lens, compared to before

Answer 1

ct In the given case, the focal length is positive, impli es that it is convex lens Diagram is showed at bottom of solution Use lens equati on jd。 8 40 d di = 10 cm Solve for image distance From the definition of magnification d. d, h, 10 cm h 4010 Solve for image height h-2.5 cm If movedlens a little then the image move to the left and get shorter you immerse the object - lens combinati on in a liquid that has an index ofrefraction larger than that of the lens materi al then The image is on the same si de of the lens as before, but in a different place

The ray diagram is

screen F A B'