What could i do with a slide projector?

A slide projector has a converging lens whose focal length is 140.00 mm. (a) How far (in meters) from the lens?

• A slide projector has a converging lens whose focal length is 140.00 mm. (a) How far (in meters) from the lens must the screen be located if a slide is placed 145.83 mm from the lens? If the slide measures 24.0 mm (height) x 36.0 mm (width), what are the magnitudes of the (b) width (in mm) and (c) height (in mm) of its image? (a): __________ m (b): __________ mm (c): __________ mm

• Answer:

  Apply lens equation .. (real image = +v) 1/u + 1/v = 1/f 1/v = 1/f - 1/u 1/v = 1/(140mm) - 1/(145.83mm) = 0.000286 .. .. .. ►v = 3502 mm .. 3.50 m Magnification M = v/u .. .. 3502mm / 146mm .. .. M = 24.0 Image width = 36mm x 24 .. ... ►w = 864 mm Image height = 24mm x 24 .. .. ►h = 576 mm