Question

Two converging lenses are placed 81.5 cm apart. An object is placed 1.18 m to the left of the first lens, which has a focal length of 23.6 cm. The final image is located 13.2 cm to the right of the second lens. What is the focal length of the second lens? Submit Answer Tries o/99 What is the total magnification? Suomit Answer Tries 0/99

Answer 1

a)

From lens law

1/f1 = 1/u1 + 1/v1

1/23.6 = 1/81.5 + 1/v1

v1 = 33.22 cm

now u2 = 81.5 - 33.22 = 48.28 cm

1/f2 = 1/u2 + 1/v2

1/f2 = 1/48.28 + 1/13.2

f2 = 10.37 cm

b)

Total magnification of system,

M = m1*m2

M = (-33.22 / 118)*(-13.2 / 48.28)

M = 0.077