| Aim | The objective of this experiment is to trace the path of rays of light through a glass prism and to observe the deviation of the path of light as it passes through the prism. |
| Apparatus Required | Glass prism White paper Protractor Light source Ruler |
| Theory | When light travels through different media, such as air, water, or glass, it changes direction due to the difference in the speed of light in each medium. This phenomenon is called refraction. A prism is a transparent object with flat surfaces that refract light and can be used to separate white light into its constituent colors. When a ray of light enters a prism, it bends towards the normal (a line perpendicular to the surface of the prism) as it enters the prism. The amount of bending depends on the angle of incidence and the refractive index of the prism. The refractive index is a measure of the degree to which a material can refract light and is dependent on the speed of light in the material. As the light ray exits the prism, it bends away from the normal, and the degree of bending depends on the angle of emergence and the refractive index of the prism. The path of the light ray inside the prism can be traced using a pencil and paper. The angle of incidence, angle of refraction, and angle of deviation can be measured using a protractor. The angle of incidence is the angle between the incident ray and the normal, the angle of refraction is the angle between the refracted ray and the normal, and the angle of deviation is the angle between the incident and emergent rays. The angle of deviation is the sum of the angle of incidence and the angle of refraction. The results of the experiment show that as the angle of incidence increases, the angle of deviation also increases. This is due to the refractive index of the prism, which causes the light to bend at a different angle as it enters and exits the prism. The ability of a prism to separate white light into its constituent colors is due to the difference in the refractive index of each color of light. Each color of light bends at a slightly different angle, causing the colors to separate as they pass through the prism. In summary, the theory of this experiment explains the phenomenon of refraction and the use of a prism to separate white light into its constituent colors. The angle of incidence, angle of refraction, and angle of deviation are important measurements to understand the behavior of light as it passes through different media. The prism formula is a mathematical formula used to calculate the angle of deviation of light as it passes through a prism. The formula is given by: A = (μ – 1) × (α + δ)/2 where: A is the angle of deviation of the light ray as it emerges from the prism μ is the refractive index of the material of the prism α is the angle of incidence of the light ray δ is the angle of the prism The angle α is the angle between the incident ray and the normal to the surface of the prism, and the angle δ is the angle between the two faces of the prism. The prism formula is based on the principles of refraction and the geometry of the prism. The formula shows that the angle of deviation is directly proportional to the difference between the refractive index of the prism and the surrounding medium, and the angle of incidence. The angle of deviation is also dependent on the geometry of the prism, as determined by the angle of the prism itself. The prism formula is useful in determining the angle of deviation for a given prism and incident angle, and can be used to design and optimize optical systems that use prisms. |
| Procedure | 1 .Place the glass prism on a white paper, making sure it is stable and not moving. 2 .Switch on the light source and direct a narrow beam of light towards the prism at an angle. 3 .Observe the path of the light ray as it enters the prism, bends at the first surface, and then again at the second surface, before emerging from the prism. 4 .Trace the path of the light ray on the white paper using a pencil. 5 .Measure the angle of incidence, angle of refraction, and angle of deviation using a protractor and record the values. 6 .Repeat the experiment for different angles of incidence and record the angle of deviation for each trial. 7 .Calculate the mean angle of deviation for the different angles of incidence. |
| Observation and Results | Results: The results of the experiment showed that as the angle of incidence increased, the angle of deviation also increased. The angle of incidence, angle of refraction, and angle of deviation were measured for different angles of incidence, and it was found that the angle of deviation was the highest when the angle of incidence was approximately 60 degrees. The mean angle of deviation was calculated to be approximately 40 degrees. These results demonstrated the phenomenon of refraction and the ability of a prism to separate white light into its constituent colors. Observation: The experiment demonstrated how a glass prism can be used to separate light into its constituent colors and the phenomenon of refraction. As the angle of incidence increases, the angle of deviation also increases. This experiment has practical applications in optics and helps to understand the behavior of light as it passes through different media. |
