Yr 10 Light Book Experiment 1

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Year 9 Science Repeat using a piece of smooth aluminium foil held in place of the mirror. Tilt the top of the foil slightly toward the ray box so that any INTRODUCTION reflected light can be seen on your sheet of paper (you may need a Some objects can be seen because they emit light (are luminous). new page). However, everything else we see around us, we see because the objects reflect light. Some of these objects reflect so well that a perfect image is produced. We call these particular objects mirrors. b) Once again trace the ray paths. What do you see? REQUIREMENTS • Ray Box • Parallel Ray gate • 6V Supply • White Paper or Pasteboard • Mounted Plane Mirror • Aluminium Foil Lightly crinkle the surface of the aluminium foil and repeat this part of the experiment by carefully tracing the rays of light and labelling your 1. REFLECTIONS FROM DIFFERENT SURFACES diagram. Set up the equipment as given in the diagram below. Insert the ray gate so that a number of parallel rays are being emitted. Don’t forget to put c) Explain the difference in the behaviour of the reflected light in your paper or book page underneath to trace the ray paths. terms of the surfaces used. mirror paper ray box 2. REFLECTION FROM A MIRROR Turn the ray gate so that only a single ray of light is emitted. Now study Direct four parallel rays of light at an angle of about 45° to the plane the reflection of a single ray of light from a plane mirror. mounted mirror. Reflecting surface a) Trace the position of the ray box and mirror and the ray paths. Incident ray Label your diagram. What happens to the rays of light? Angle of incidence Ray box normal Place the mounted mirror on the blank page in your practical book. Direct a single ray of light on to the mirror (see diagram). 07 Reflection Page 1 of 2 Mark the incident ray, the reflected ray and the reflecting surface of the mirror. Remove the mirror. EXERCISES Draw a line perpendicular to the mirror from the point where the incident ray meets the reflecting surface. This line is called the normal 1. Explain why the light from an approaching car may dazzle you if the to the mirror (see diagram). road is wet. The angle between the incident ray and the normal is called the angle of incidence. a) What is meant by "the angle of reflection"? 2. Explain why you can see a pencil even though it is non-luminous. Measure the angle of incidence and the angle of reflection. Enter your results on the table. Repeat the experiment for different angles of incidence by moving the ray box or mirror. Obtain four sets of results. EXPERIMENT ANGLE OF INCIDENCE ANGLE OF REFLECTION 1 3. A piece of white paper reflects a lot of light, yet you cannot see 2 your own image in the paper. Explain. 3 4 b) What can you conclude from your table of results? 07 Reflection Page 2 of 2 .

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