A camera is equipped with a lens with a focal length of 31 c
     A camera is equipped with a lens with a focal length of 31 cm. When an object 3.0 m (300 cm) away is being photographed, what Is the magnification   
  
  Solution
1 / f = 1 / v + 1 / u
1 / v = 1 / 31 - 1 / 300
v = 34.57 cm = 0.35 m
magnification = v / u = 0.35 / 3.0
= 0.117

