Question

1. What is the image distance and image size if a 10.00 cm. tall light bulb placed a distance of 91 cm. from a convex lens having a focal length of 30.8 cm ?

Answer 1

$1/f=1/d_i+1/d_o\to1/d_i=1/f-1/d_o=1/30.8+1/91$

$d_i=23\ (cm)$

$h_i/h_0=-d_i/d_o\to h_i=-d_i\cdot h_o/d_o=-23\cdot10/91=-2.5\ (cm)$