Help With PHYSICS!?

Question

A slide projector has a converging lens whose focal length is 105 mm.

(a) How far (IN METERS) from the lens must the screen be located if a slide is place 108 mm from the lens.?

(b) If the slide measures 24.0 mm x 36.0 mm , what are the dimensions ( in mm) of its image?

Answer 1

v = screen distance

m = magnification

(a)

1 / 0.108 + 1 / v = 1 / 0.105

v = 3.78 m.

(b)

m = 3.78 / 0.108 = 35

35 * 24.0 / 10^3 = 0.84 m

35 * 36.0 / 10^3 = 1.26 m.

Dimensions are: 0.84 m x 1.26 m.