Your eyes trace the light rays backwards as straight lines to the point they would have come from if they had not changed direction and as a result you see the tip of the straw as being shallower in the liquid than it really is. Figure 1: Due to refraction, a straw in a glass of water appears bent when an observer looks down at an angle from above the water surface. Refractive index The speed of light and therefore the degree of bending of the light depends on the refractive index
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.
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.
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 blue line and the orange line are equal and so by basic geometry the reflected line and the red line are equal in length. Since we know that a straight line is the shortest distance between two points we can say that the angle that the light makes at the reflective medium that minimizes the distance between the two points (if it has to first travel to the reflective medium) is the angle that the light beam makes with the surface of the reflective medium. Since the light is traveling at a constant speed the minimum distance also corresponds to the minimum time. So we see that the minimum time proposition explains the law of the reflection of light. We can now explore the more complicated scenario of light traveling from one medium to another.
Edward Gray NT1310 07/29/2013 Assignment 7 Reflection, Refraction and Degradation. The law of reflection states that if light hits a reflective surface at a certain angle, (angle of incidence), it will reflect or bounce off at the same angle, (angle of reflection.) A Mirror is a good example of reflection. Mirrors have smooth shiny surfaces that absorb very little light, so they reflect light in almost exactly the same pattern as it hits, which allows us to see a complete reflected image of objects. Mirrors can reflect images of objects because light rays bounce off an object, travel in a straight line to a mirror, bounce off the mirror, and then travel to the eye of an observer.
Experiment on finding the Refractive Index value of Perspex using Snell’s law Aim: The aim of this experiment is to find the refractive index of Perspex, using Snell’s law. By shining a ray at a prism and drawing the incoming and out coming ray, and then drawing the normal and measuring the angles. Variables: Table 1: table of variables Identify the variable(s) How will the variable(s) be changed, measured, and/or controlled? Independent variable(s) Angle of incidence Move the box around so that the ray hits the prism at different angle. Dependent variable(s) Angle of refraction Measure the angle with a protractor.
Abstract: The purpose of this experiment was to utilize a Bourden Gage, a U-tube manometer and a water piezometer to analyze the behavior of a system placed under pressure, and to test the validity of the hydrostatic pressure equation. In order to accomplish these ends, the fluids within the system (air, water and mercury) must be considered incompressible. Experimental data upholds the validity of the hydrostatic pressure equation, as both the manometer and piezometer displayed a direct relationship between system pressure and fluid height. An analysis of percent error revealed a discrepancy between the accuracy of the manometer and piezometer. At low pressure, the manometer displayed a 100% error, which trailed off smoothly to a final value of 31% at high pressure.
The behaviour is governed by the ratio of back pressure pback to total pressure p0. For pressures above psub the flow remains subsonic throughout. For pressures below psub the flow goes supersonic at the throat; the throat is choked and the maximum mass flow rate is achieved. At the design pressure pdesign the flow passes smoothly from subsonic to supersonic without shocks. To determine psub and pdesign, since A* = Athroat, use the subsonic and supersonic Mach numbers corresponding to isentropic flow with area ratio Aexit/Athroat: where Masub and Madesign are the subsonic and supersonic solutions, respectively, of Figure 1.
For one mole of gas, the difference between Cp and CV is the constant R (R is the so called universal gas constant) and represents the capacity of the gas to perform expansion work at constant applied pressure. {Cp = CV+R for an ideal gas} Since, for solids and liquids, the constant pressure and constant volume Heat Capacities are the same, the subscript p or V on the 'C' is usually dropped. Q = m C DT This means that the proportionality between the Heat flow into (or out of) an object and the Temperature change of that object is the total Heat Capacity, which can be expressed as a molar property or per mass. if m is moles and C is molar Heat Capacity if m is mass (grams) and C is the Specific Heat Q is positive for a temperature increase because the system has undergone an endothermic change of