Question

A converging lens (f = 11.0 cm) is located 23.6 cm to the left of a diverging lens (f = -4.51 cm). A postage stamp is placed 52.7 cm to the left of the converging lens. (a) Locate the final image of the stamp relative to the diverging lens. (b) Find the overall magnification.

Answer 1

using lens formula for converging lens

1/f = 1/v - 1/u

1/11 = 1/ v + 1/52.7

v = 13.9 cm

now the above image acts as object for diverging lens

object distance of which is given by

u' = 23.6 - 13.9 = 9.698 cm

now using lens formula for diverging lens

- 1/4.51 = 1/ v' + 1/9.698

v' = 3.078 cm to the left of diverging lens

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b)

m = (v/u) (v'/u')

m = ( - 13.9/52.7) ( 3.078 /9.693)

m = - 0.08371

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