1. By: Yelyzaveta Lapina, Damien Uthayakumar, Mohsen Najafi, John Unsal, Francisco Xabier Ugarte Cavagnaro

2. The purpose is:  to find out the path of light when it passes through a diverging lenses  To figure out how the three principal rays will react with a diverging lens.

3.  Ray box  Blank white sheet of paper  Diverging lens  Ruler

4.  Set up the apparatus to find the focal point (F) of the lens, place the ray box on another side of the lens to find the focal point (F’)  Adjust the ray box to produce a single ray and direct it towards the lens, so that the ray: Points in the direction of the secondary focal point of the lens Is parallel to the principal axis Passes through the optical centre of the lens  Record the results

5.  Diverging Lens  Focal length is 7 cm

6.  Diverging Lens, First principal ray  Ray is parallel to the principal axis and is refracted in such way that it appears to come from the lens’s principal focal point (F)

7.  Diverging Lens, Second principal ray  Ray points in the direction of the focal point and is refracted parallel to the principal axis

8.  Diverging Lens, Third principal ray  Ray goes through the lens’s optical centre and travels straight through

9.  The lens consists of a transparent object that has at least one curved surface and controls the direction of the light rays passing through it.  Lens is said to be diverging when parallel beams of light enter it diverge from the secondary focal point  When light passes through the concave lens, refracted rays diverge and do not intersect each other, diverging rays appear to come from the focal point.

10.  To find the image of the object it’s required to shine 3 principal rays through the lens.  The images are formed by help of these principal rays in the lens  In order to figure out if the lens is symmetrical, shine incident rays on both sides of the lens, and observe if both focal lengths are the same.  The lens which was used in the experiment was symmetrical

11. Lenses and principal rays are used in technology and they many applications:  Principal rays are used in order to get an image of the object, while using the magnifying glass, microscopes, telescopes or photo cameras.

12. Errors:  The rays from the ray box weren’t exactly parallel to each other, which changes the results.  The sheet of paper shifted slightly during the experiment altering the possible results.

13.  The priority was to find out the path in which the light beam takes when it passes through a concave lens  In concave lenses refracted rays diverge  Using the principal rays of the lens, it’s possible to find the image of the object, when the principal rays intersect they form an image