Two thin lenses with a focal length of magnitude 15.5 cm , the first diverging a

Question

Two thin lenses with a focal length of magnitude 15.5 cm , the first diverging and the second converging, are located 11.6 cm apart. An object 3.30 mm tall is placed 25.8 cm to the left of the first (diverging) lens.

Part A

How far from this first lens is the final image formed?

Express your answer in centimeters to three significant figures.

part B

Is the final image real or virtual?

Part C

What is the height of the final image?

Express your answer in millimeters to three significant figures.

Part D

Is it upright or inverted?

please explain the answers

thanks

Explanation / Answer

f is the focal length of the combination.
1/f = 1/f1 + 1/f2. - d/(f1.f2)
f1 = - 15.5 cm
f2 = +15.5 cm
1/f = + 11.6/240.25
f = 20.7 cm
---------------------
1. v = uf/(u-f) = 25.8*20.7/5.1 = 104.72 cm
2. v is positive and is on the other side of the lens combination.
Image is Real
3 and 4. m = -v/u = - 104.72/25.8 = -4.06
Minus indicates that the image is inverted.
The height of the image is 4.06* 3.3 = 13.4 mm

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