1. a) Redraw the previous figure. b) Determine the angle of incidence at the point I. c) What are the phenomena does the incident ray undergo at point I? When a ray is incident from one transparent medium to another one, part of the incident ray is refracted while the other part is reflected. d) Calculate the speed of light inside the glass plate. On the figure

2. The angle of refraction corresponding to SI is 31 0. e) Calculate the angle of deviation. f) Draw the refracted ray corresponding to SI. On the figure 50 0 31 0 50 0 I J g) The refracted ray corresponding to SI hits the surface CD at point J. i) Compare the angle of incidence at J and the angle of refraction at I. Justify. (Alternating angles) ii) The ray IJ will cross from glass into air. Why? iii) Complete, with justification, the path of the ray at J till it emerges from the rectangle. principle of reversibility of light S

3. 50 0 31 0 50 0 I J h) By referring to the previous figure, which one of the two mediums, (air) or (glass), is less refractive? Justify. S Yes, If a ray of light travels from a less refracting into a more refracting medium, it is refracted towards the normal in all cases.

4. ( ‑ II ‑ ) Exercise Two: Characteristics of a lens. An object AB is placed perpendicularly to the optical axis of a lens (L), where the image A’B’ of AB is obtained on a screen (E) which is placed behind the lens (L) which is not represented in the given diagram that is drawn to the scale 1/5 ( for vertical and horizontal scale) a)Redraw the figure on a graph paper using the same scale. b) What is the direction of the image A’B’? Justify. c) Deduce the nature of the image A’B’? Justify. On the figure The image is inverted since it has opposite sense w.r.t the original object. An inverted image is a real image.

5. d) What is the nature of the lens? Justify The lens is converging since the image is real. e) Determine graphically the size of the object. f) Specify the position of the optical center (O) of the lens and then draw the lens (L). Any ray incident from point A to the lens will emerge through its real image (A’) O is the intersection between the AA’ and the optical axis. F’ g)A ray incident from the point (A) parallel to the optical axis meets the lens at a point I. Draw the path of the emergent ray. I On the figure h) Specify the position of the image focus F’. In converging lens : Any ray parallel to the optical axis will pass through the image focus. F’ is the intersection between the IA’ and the optical axis. O

6. F’ I i) Determine the focal length of the lens. j) Deduce the vergence of the lens. O

7. F’ I K )Where the object AB should be placed in order to give an image on a screen of size larger to that of the object. What is the role of the lens in this case? Justify. l) Continue with justification the path of the ray BI. Any ray incident from point B to the lens will emerge through its real image (B’) O