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n n incident ray reflected ray refracted ray N Figure 1 The law of reflection states that 'the angle of incidence equals the angle of. It has been found that the behaviour of reflected and refracted rays can each be described by a law. Note that the reflected amplitude for the light polarized parallel to the incident plane is zero for a specific angle called the Brewster angle. angle of reflection and the angle the refracted ray makes is called the angle of refraction. These curves are the graphical representation of the Fresnel equations. Physics Physics questions and answers Part 1.

at a shallow angle of incidence) you will clearly see the reflection of the surroundings and sky, and little or no detail of the bottom of the pool. When a ray of light undergoes refraction, a straight line graph is obtained by plotting sine of angle of incidence versus sine of angle of refraction. When the incident angle is equal to the critical angle, the ray will no longer transmit or pass into the second material instead, it will just skim along the. steep angle of incidence) you will see the bottom of the pool.Īs you look out across the pool (i.e. is the angle between the reflected ray and the normal at the point of incidence (see Fig. The critical angle is the angle of incidence for which there is no refracted ray, or in other words the light ray is totally reflected. So if you stand at the edge of a pool and look down near your feet (i.e.

Above 50 degrees the percentage of light that is reflected increases steeply. Then the reflected ray makes an angle r with. Assume the incoming light ray makes an angle i with the normal of a plane tangent to the boundary. At least some part of the incoming wave remains in the same medium. Light travelling at a water surface at angles of incidence less than 50 degrees mostly penetrate the water. Reflection is the abrupt change in the direction of propagation of a wave that strikes the boundary between two different media. If you were to draw the amount of light refracted at the boundary when light travels from air to water you would get the following graph: (3% of the light will be reflected backwards) (Please note: In nearly all questions in exams at basic level, the proportion of light that is reflected is not taken into account)īright beam at 0° – perfectly in line with the normal line. It is just in different proportions depending on the angle. When a ray of light travels from a fast to a slow medium, for instance air to water, at different angles of incidence (degrees to the normal) you will always get some surface boundary reflection and you will always get some refraction. The angle of reflection equals the angle of incidence.Again, you don't need this in an exam – it is just interesting to know. The law of reflection is very simple: The angle of reflection equals the angle of incidence. \): Moonlight is spread out when it is reflected by the lake, since the surface is shiny but uneven.