Describe an activity to show that …

• First law of reflection states that the incident ray, the normal to the surface at the point of incidence and the reflected ray, all lie in the same plane.

Take a torch and cover its glass with a chart paper which has three slits. Spread a sheet of chart paper on a smooth wooden board. Fix a plane mirror strip vertically on the chart paper. Now direct the beam of light on the mirror from the torch with slits. Place the torch in such a way that its light is seen along the chart paper on the board. Now adjust its position so that the light from the torch strikes the plane mirror at an angle. The plane mirror reflects the three rays of light falling on it.

Similarly, place a lighted candle in front of a plane mirror. Try to see the flame of the candle in the mirror. It appears as if a similar candle is placed behind the mirror. The candle, which appears behind the mirror, is the image of the candle formed by the mirror. The candle itself is the object and now moves the candle to different positions in front of the mirror. The flame appears on top of the candle as in the object is called erect. An image formed by a plane mirror is erect and of the same size as the object.