# Angle of incidence and reflection relationship questions

### The Law of Reflection Answer to What is the relationship between angle of incidence and the angle of reflection?. What relationship holds between the angle of incidence and the angle of reflection? The relationship between the incident angle and the refraction angle is that. A tutorial including problems with solutions on reflection of light rays. of incidence (2) The angle of incidence and the angle of reflection have the same size.

Examples of its use are shown below: Example A Calculate the critical angle for the crown glass-air boundary.

### BBC Bitesize - GCSE Physics (Single Science) - Reflection and refraction - AQA - Revision 1

Refer to the table of indices of refraction if necessary. The solution to the problem involves the use of the above equation for the critical angle. Of all the possible combinations of materials that could interface to form a boundary, the combination of diamond and air provides one of the largest differences in the index of refraction values. This peculiarity about the diamond-air boundary plays an important role in the brilliance of a diamond gemstone. Having a small critical angle, light has the tendency to become "trapped" inside of a diamond once it enters. A light ray will typically undergo TIR several times before finally refracting out of the diamond.

• Refraction of light
• Reflection and refraction
• The Law of Reflection

Because the diamond-air boundary has such a small critical angle due to diamond's large index of refractionmost rays approach the diamond at angles of incidence greater than the critical angle. This gives diamond a tendency to sparkle. The effect can be enhanced by the cutting of a diamond gemstone with a strategically planned shape. The diagram below depicts the total internal reflection within a diamond gemstone with a strategic and a non-strategic cut. Use the Find the Critical Angle widget below to investigate the effect of the indices of refraction upon the critical angle. Simply enter the index of refraction values; then click the Calculate button to view the result. Use the widget as a practice tool.

Check Your Understanding 1. Suppose that the angle of incidence of a laser beam in water and heading towards air is adjusted to degrees. Use Snell's law to calculate the angle of refraction? Explain your result or lack of result. See Answer Good luck! This problem has no solution. The angle of incidence is greater than the critical angle, so TIR occurs. There is no angle of refraction. Aaron Agin is trying to determine the critical angle of the diamond-glass surface. He looks up the index of refraction values of diamond 2. Aaron hits the calculator and throws it own the ground a few times; he then repeats the calculation with the same result.

## The Critical Angle

In the diagram, the ray of light approaching the mirror is known as the incident ray labeled I in the diagram. The ray of light that leaves the mirror is known as the reflected ray labeled R in the diagram. At the point of incidence where the ray strikes the mirror, a line can be drawn perpendicular to the surface of the mirror.

This line is known as a normal line labeled N in the diagram. The normal line divides the angle between the incident ray and the reflected ray into two equal angles. The angle between the incident ray and the normal is known as the angle of incidence. The angle between the reflected ray and the normal is known as the angle of reflection. 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.

## Reflection of Light Rays, Examples and Solutions

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. 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.

Experimental Verification of The Laws of Reflection

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. 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.