A converging lens with a focal length of 50 cm is used to create an image of a 1.8 mm long ant. If the lens is placed so that the image of the ant is 8 mm long, inverted, and viewed on a screen held some unspecified distance on the other side of the lens to the ant, how far away from the ant was the lens placed?

An object is placed 25 cm in front of a converging lens of focal length 20 cm. 30 cm past the first lens is a second diverging lens of magnitude focal length 25 cm. What are the resulting image position relative to second lens and total magnification of the object in this setup?

Two converging lenses, both with focal lengths 34.9 cm are placed a distance 78.9 cm apart. An object is placed 87.5 cm from the 1st lens. Where is the final image located relative to the 2nd lens? Let + be the back side and - be the front side regarding this distance from the 2nd lens. Measure this in cm.

A converging lens of focal length 20 cm is placed 30 cm in front of another converging lens of focal length 4.0 cm. An object is placed 100 cm in front of the first lens. Determine(a) the location of the final image, (b) its orientation, and (c)whether it is real or virtual.

Where is the near point of an eye for which a contact lens with a power of 2.60 diopters is prescribed? (Assume that near point for an average viewer is 25  cm .) Where is the far point of an eye for which a contact lens with a power of -1.20 diopters is prescribed for distant vision?

Consider a thin lens L1 with a focal length of -10cm, and a second lens L2 with a focal length of +5cm. (a) If the two lenses are placed very close together, but with an air gap between them, and an object is placed 25 cm from the lens combination, where is the location of the image? Describe the image: real or virtual, inverted or erect, and magnified or shrunk. (b) If lens L2 is now moved 10 cm away from lens L1, where is the location of the image? Again describe the image: real or virtual, inverted or Erect, and magnified or shrunk.