# Homework Help: Combination of spherical lenses

1. Mar 15, 2013

### jo 92

Two thin lenses having focal lengths of +15 cm and -15 cm are positioned 60 cm apart. A bird stands 25 cm in front of of the converging lens.

a. describe the image of the bird. Is it real or virtual? Upright or inverted? Magnified or reduced?

b. If the bird is 10 cm in height, what is the height of its image?

2. Mar 15, 2013

### jo 92

Combination of lenses

Two thin lenses having focal lengths of +15 cm and -15 cm are positioned 60 cm apart. A bird stands 25 cm in front of of the converging lens.

a. describe the image of the bird. Is it real or virtual? Upright or inverted? Magnified or reduced?

b. If the bird is 10 cm in height, what is the height of its image?

3. Mar 15, 2013

### jo 92

Combination of lenses (Convex & Concave)

Two lenses are placed on the x axis of a line. The first lens is a diverging lens with a focal length of 9 cm placed x= -8 cm. The second lens is a converging lens with focal length 4 cm placed x= 6 cm. If an object is placed at x= -12 cm, what is the position of the image, image type (virtual or real), and the magnification of the image?