Question

A spiracle polish metallic ball is uses a diverging mirror with a focal length of -20 cm a bird 25 cm tall standing 50 cm away Looks directly at the mirror what are the size and position of the birds image

Answer 1

1/f = 1/i + 1/o thin lens equation

1/i = 1/f - 1/o

i = o * f / ( o - f) = 50 * (-20) / (50 - (-20)) = -14.3 cm

The final image is erect and 14.3 cm behind the curved surface

M = -o / i = 14.3 / 50 = .29 magnificaton of object

S = .29 * 25 cm = 7.1 cm appearance of bird in mirror (height)