Homework: 1. An object placed in front of a lens at 6 cm. The lens has a focal length of 10 cm. Where does the image is formed and describe the image. 2. An object exists in front of a bi-concave lens of a focal length -6 cm at a distance of 14 cm. Find the position of the image and describe it . 3. A converging lens has a focal length of 10 cm. (a) Find the image distance for an object is placed 30 cm in front of the lens. Describe also the image and construct a ray diagram. (b) Repeat what you have done in (a) for an object placed 20 cm in front of the lens . (c) repeat what you did in (a) for an object 5 cm in front of the lens. 4. A diverging lens has a focal length of 10 cm. Construct a ray diagram, find the image position, and describe the image for the following positions of an object placed in front of the lens at: (a) 30 cm (b) 20 cm (c) 5 cm. 5. If a convex lens has radii of curvature 20 cm and 10 cm, it has a refractive index 1.5. (a) Calculate the focal length of the lens. (b) Find the image distance, describe the image, and construct a ray diagram of an object placed at 20 cm in front the lens.