Question

Use the worked example above to help you solve this problem. Two converging lenses are placed d₂ = 24.0 cm apart, as shown in figure a, with an object d₁ = 36.0 cm in front of lens 1 on the left.

(a) If lens 1 has a focal length of f₁ = 12.0 cm, locate the image formed by this lens and determine its magnification.

q =	cm
M =

(b) If lens 2 on the right has a focal length of f₂ = 24.0 cm, locate the image formed and find the total magnification of the system.

q =	cm
M =

EXERCISE HINTS:  GETTING STARTED | I'M STUCK!

If the two lenses in the figure are separated by 12.0 cm, locate the final image and find the magnification of the system. [Hint: The object for the second lens is virtual!] (Use the necessary information from the Practice It portion of the problem.)

q =	cm
M =

Answer 1

1/v + 1/u = 1/f

part 1: u = 36.cm f1 = 12.cm

put in above formulae

V1 = 18 cm

magnification m = -18/36 = -0.5

part2:

now to define object distance from lens.

u2 = V1 + d2 = 24 - 18 = 6 cm

f2 = 24.cm

1/v2 + 1/u2 = 1/f2

V2 = -8 cm

magification = v/u = V2/u2 x V1/u1 = -8/6 x 0.5 = -0.66

Answer 2

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