Question

Problem 6

Part 1

A certain slide projector has a 100 mm focal length lens. (a) How far away is the screen, if a slide is placed 103 mm from the lens and produces a sharp image? (b) If the slide is 24.0 by 36.0 mm, what are the dimensions of the image?

Part 2

A doctor examines a mole with a 15.0 cm focal length magnifying glass held 13.5 cm from the mole (a) Where is the image? (b) What is its magnification? (c) How big is the image of a 5.00 mm diameter mole

I really need part 2 please

Answer 1

Part 1

(a)

Using the lens equation

1/u + 1/v = 1/f

1/v = 1/f - 1/u

1/v = 1/100mm - 1/103mm

v = 1/0.00034

v = 3433.33mm

Image distance = 3.43 m

(b)

Magnification = v/u

m = 3433.33 mm / 103 mm = 33.33

Image dimensions

(24mm*33.33) ,(36mm*33.33)

800 mm, 1200 mm

0.8 m, 1.2m

Part 2

(a)

The position of the image is:

v = 1 / ((1 / f) - (1 / u))

v = 1 / ((1 / 0.15 m) - (1 / 0.135 m))

v = - 1.35 m

v = -135 cm

(b)

The magnification of the image is:

M = - v / u

M = - 1.35 m / - 0.135 m

M = 10 times

(c)

image is:

0.005 m x 10 = 0.05 m = 5 cm