Reflection of Light Rays, Examples and Solutions
This relationship between the angles of incidence and refraction and the indices of the refraction and/or reflection of light at a boundary between two materials. A beam of light incident on the metal surface is reflected. All reflected light obeys the relationship that the angle of incidence equals the angle of reflection. Experiment Setup – Test the Hypothesis An example: Variables: incident and reflected beam angles relationship between incident and reflected angles.
These two angles are labeled with the Greek letter "theta" accompanied by a subscript; read as "theta-i" for angle of incidence and "theta-r" for angle of reflection. The law of reflection states that when a ray of light reflects off a surface, the angle of incidence is equal to the angle of reflection.
Reflection and the Locating of Images It is common to observe this law at work in a Physics lab such as the one described in the previous part of Lesson 1. To view an image of a pencil in a mirror, you must sight along a line at the image location.
BBC Bitesize - GCSE Physics (Single Science) - Reflection and refraction - Eduqas - Revision 3
As you sight at the image, light travels to your eye along the path shown in the diagram below. The diagram shows that the light reflects off the mirror in such a manner that the angle of incidence is equal to the angle of reflection. It just so happens that the light that travels along the line of sight to your eye follows the law of reflection. The reason for this will be discussed later in Lesson 2. If you were to sight along a line at a different location than the image location, it would be impossible for a ray of light to come from the object, reflect off the mirror according to the law of reflection, and subsequently travel to your eye.
Only when you sight at the image, does light from the object reflect off the mirror in accordance with the law of reflection and travel to your eye. This truth is depicted in the diagram below. For example, in Diagram A above, the eye is sighting along a line at a position above the actual image location. For light from the object to reflect off the mirror and travel to the eye, the light would have to reflect in such a way that the angle of incidence is less than the angle of reflection.Snell's law of Refraction
In Diagram B above, the eye is sighting along a line at a position below the actual image location. In this case, for light from the object to reflect off the mirror and travel to the eye, the light would have to reflect in such a way that the angle of incidence is more than the angle of reflection. Neither of these cases would follow the law of reflection. In fact, in each case, the image is not seen when sighting along the indicated line of sight.
It is because of the law of reflection that an eye must sight at the image location in order to see the image of an object in a mirror.
Check Your Understanding 1. Consider the diagram at the right. Which one of the angles A, B, C, or D is the angle of incidence? Angle C is the angle of reflection angle between the reflected ray and the normal. A ray of light is incident towards a plane mirror at an angle of degrees with the mirror surface. What will be the angle of reflection?
If an object does not emit its own light which accounts for most objects in the worldit must reflect light in order to be seen. All Things Reflected What is it about objects that let us see them? The walls in the room that you are in do not emit their own light; they reflect the light from the ceiling "lights" overhead.
Polished metal surfaces reflect light much like the silver layer on the back side of glass mirrors. A beam of light incident on the metal surface is reflected. Reflection involves two rays - an incoming or incident ray and an outgoing or reflected ray.
In Figure 1 we use a single line to illustrate a light ray reflected from the surface. The law of reflection requires that two rays are at identical angles but on opposite sides of the normal which is an imaginary line dashed in Fig. We show in Fig. The dashed line normal is perpendicular to the surface. All Things Equal All reflected light obeys the relationship that the angle of incidence equals the angle of reflection.