1. Aflashlight beam strikes the surface of a pane of glass (n = 1.5) at a 20 angle to the normal. Calculate the angle of refraction. Draw a diagram and indicate all the parameters. 2. Abeam of light is shining upwards from beneath the glass at a 35 angle to the vertical. Calculate the angle of refraction (n for glass = 1.5). Draw a diagram and indicate all the parameters. 3. Light travels from a plastic material of with n=1.43 to air. Calculate the critical angle for plastic-air interface. Draw a diagram and indicate all the parameters. 4. Atypical human eye lens has a focal length of 2.4 cm. Suppose a person looks at a small candle, located 30-cm away from her. (a) Determine the location of its image. What is the magnification? (b) If the candle is 5.5 cm in size, determine the size of the candle's image. (c) Draw a ray diagram indicate object distance (do ), image distance (di ) and focal length of the lens (f ). Describe the image formed. 1. 4, If you want to start a fire using sunlight, which kind of lens would be most effective? (A) Concave or Diverging lens (B) Convex or Converging lens (C) Both (A) and (B) Sunlight is observed to focus at a point 16.5 cm behind a lens. What kind of lens is it? What is its power? A 7-cm-high pencil is located 25-cm in front of a converging lens with a focal length of 15-cm. (a) Determine the location of its image. (b) Calculate the magnification, size of the pencil's image and the power of this lens. (c) Draw aray diagram - Indicate object distance (do), image distance (di) and focal length of the lens (f). Describe the type of image formed. A nature photographer wishes to shoot a 30-m-tall tree from a distance of 80 m. (a) What type of lens is used in this camera? (b) Draw a ray diagram. Indicate the object distance (do), image distance (di) and focal length of the lens (f). Describe the image formed. (c) What focal-length lens should be used if the image fills the 24-mm height of the sensor