Objective The purpose of this experiment is to prove the laws of reflection and refraction, and to determine the angle of the total internal reflection and the index of refraction in the experiment. Theory The theory being experimented in this procedure is that of Willebrord Snell. From his theory we understand that the incident ray, the normal line and the refracted ray all lie on the same plane. We also understand that the relationship is defined in a ratio with the following equation; Which means that the ratio of the sine of the angle of incidence to the sine of the angle of refraction, I equal to the ratio of the speed of light in the original medium and the speed of light in the refracting medium. Procedure We set up the optics track, light source and the ray table.
Snell's Law In the previous sections we studied light reflecting off various surfaces. What happens when light passes from one medium into another? The speed of light, like that of all waves, is dependent on the medium through which it is travelling. When light moves from one medium into another (for example, from air to glass), the speed of light changes. If the light ray hits the boundary of the new medium (for example the edge of a glass block) at any angle which is not perpendicular to or parallel with the boundary, the light ray will change its direction through the next medium, or appear to `bend'.
Investigating the various phenomena which occur when monochromatic light undergoes diffraction Title: Determine the wavelength of a monochromatic light source (laser). Measure the groove spacing of a CD and the diameter of powder spores using diffractive methods. Aim: The aims of this experiment are to determine the wavelength of the monochromatic light source and to determine the groove spacing of a CD and the diameter of the Lycopodium powder. Introduction: There are three parts to this experiment in the first part a diffraction grating is used to diffract light from a laser (monochromatic source of light). By measuring the angles of diffraction and by calculating the grating spacing, the wavelength of the light may be calculated.
How is this type of wave created? How was this type of wave discovered? When was this type of wave discovered? Fiber optic signals are created by turning electronic signals in to light. Guiding of light by refraction, the principle that makes fiber optics possible, was first demonstrated by Daniel Colladon and Jacques Babinet in Paris in the early 1840s.
An optimised imaging modality would result from a combination of these properties. One such emerging technique that achieves this is Cherenkov Luminescence Imaging (CLI). CLI harnesses Cherenkov radiation to image radionuclides using OI instruments2. Cherenkov radiation is a well known phenomenon that arises when charged particles, such as β- or β+ travel through an optically transparent material with a velocity that exceeds the speed of light in the material. As the particle travels through the medium it loses kinetic energy by polarizing the electrons of the given material.
REFLECTION, REFRACTION, DIFFRACTION Reflection – waves bounce off a surface Refraction – waves bend when they pass though a boundary Diffraction – waves spread out (bend) when they pass through a small opening or move around a barrier REFLECTION - when a wave encounters a barrier, it can reflect the bounce off the obstacle - i.e. light = mirror; sound = echo - most objects we see reflect light rather than emit their own light - Fermat’s principle = light travels in straight lines and will take the path of least time Laws of Reflection 1. The angle of incidence equals the angle of reflection (true for both flat and curve mirrors) 2. The incidence ray, reflected ray, and the normal all lie in the same plane. Specular vs. Diffuse Reflection - in diffuse, waves are reflected in many different ways form a rough surface - in specular, waves are reflected in the same direction from a smooth surface REFRACTION (light) - when one medium ends and another begins, that is called boundary - when a wave encounters a boundary that is denser, part of it is reflected and a part of it is transmitted - the frequency of the wave is not altered when crossing the boundary / barrier but the speed and wavelength are - the change in speed and wavelength can cause the wave to bend if it hits the boundary at an angle other than 90 degrees - this bending as light enters the water can cause objects under water to appear at a different location than they actually are REFRACTION (sound) - sound waves bend when passing into cooler / warmer air because the speed of sound depends in the temperature of the air - sound travels slower in cooler air REFRACTION (water) - water waves bend when they pass from deep water into shallow water, the wavelength shortens and they slow down.
The purpose of this lab was to use a spectroscope to analyze the light produced by different light sources. We looked at six different light sources through the spectroscope, including incandescent light, helium, neon, mercury, nitrogen, and fluorescent light. When viewing these light sources through the spectroscope we could see different types of spectra. Spectrum is a band of colors, as seen in a rainbow, produced by separation of the components of light. The different types of spectra are continuum spectrum, absorption spectrum, and emission spectrum.
We can now explore the more complicated scenario of light traveling from one medium to another. Below is a diagram showing the path that the light travels. Here we know that the light is traveling from the initial point to the final but we are trying to find the x value (where it crosses the two mediums) that minimizes the time taken. If we look at this diagram it is clear that in general the total time that the beam travels to get from point x1,y1to point x2,y2 is: Tx=x-x12+y12v1+x2-x2+y12v2 If we consider Fermat’s principle of least time to be true then the true time taken is that for which the function is a minimum. To find this we take the derivative of T(x) and set it equal to zero.
There are many useful devices that form images by refraction, such as eyeglasses, cameras, binoculars, microscopes, and telescopes. Gap loss: gap loss happens when the signal from one end of a piece of cable is transferred to another, but there is a space, breakage, or gap between them. Since fiber optics transmit data via light the light can cross this gap, but spreads out and is weakened and diffused
Purpose: When light travels through different mediums, it is being refracted. The purpose of this lab is to test Snell’s law of refraction. Hypothesis: The angles of refraction that I predicted from the angle of incidences by using Snell’s Law are below on the predicted angle Column. To obtain these values I used the index of refraction of crown glass because it is more likely close to the glass (plexiglass) that we are using. Angle of Incidence 0° 10° 20° 30° 40° 50° 60° Predicted angle of refraction 0 6.56° 13.0° 19.2° 25.02° 30.27° 34.74° Variables and Controls: Independent Variable: The angle of the light coming from the ray box or the angle of incidence Dependent Variable: The angle of refraction on the plexiglass.