My answer is wrong A 5.57-mm-high firefly sits on the axis of, and 11.9 cm in fr

Question

My answer is wrong

A 5.57-mm-high firefly sits on the axis of, and 11.9 cm in front of, the thin lens A, whose focal length is 6.03 cm. Behind lens A there is another thin lens, lens B, with focal length 20.3 cm. The two lenses share a common axis and are 61.3 cm apart. Is the image of the firefly that lens B forms real or virtual? How far from lens B is this image located (expressed as a positive number)? What is the height of this image (as a positive number)? Is this image upright or inverted with respect to the firefly?

Explanation / Answer

here ,

height of fly , ho = 5.57 mm

for the lens ,

di1 = 11.9 cm

f = 6.03 cm

1/f = 1/di1 + 1/do2

1/6.03 = 1/11.9 + 1/di1

di1 = 12.22 cm

for the second lens ,

do2 = 61.3 - 12.22

do2 = 49.1 cm

f2 = 20.3 cm

Using lens formula

1/f2 = 1/di2 + 1/do2

1/20.3 = 1/49.1 + 1/di2

di2 = 34.6 cm

the second image is real
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the image is located at 34.6 cm from the lens B
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hi = 5.57 * (34.6/49.1) *(12.9/11.9)

hi = 4.26 mm

the height of this image is 4.26 mm

the image is upright

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