Place a dot on the piece of paper at the point where the laser light originates from the pointer and where it leaves the refraction cell after passing through the water. 6. Use a ruler to draw a line from the points placed on the paper to the point where the parallel lines intersect. 7. Use a protractor to measure the angle from the reference line to the lines drawn in step 6.
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.
By measuring the angles of diffraction and by calculating the grating spacing, the wavelength of the light may be calculated. The light source used in the experiment should be a monochromatic light source as the experiment requires light of a single wavelength in order for the wavelength to be calculated. The second part of the experiment demonstrates how to determine the measurement of the groove spacing of a CD. The CD is used as a reflective grating; the light is reflected from the surface of the cd some of the reflected angles will give rise to constructive maxima, similar to a diffraction grating. The last part of the experiment is to determine the measurement of the diameter of powder spores by passing a monochromatic light source through a circular aperture and producing a diffraction pattern of concentric rings.
We rotated the ray table until the refracted ray disappeared completely and only the reflected ray was visible. This is the angle of incidence. This gave us our angle of incidence theoretical value. From this we were also able to calculate the angle of refraction. Results
Dependent variable(s) Angle of refraction Measure the angle with a protractor. Controlled variable(s) The refractive index The position of the Perspex Trace it on a piece of paper, this is where it will be placed it it got moved. Same light source Same ray box Same protractor and unit Use the same protractor Same piece of Perspex Use only one Perspex prism Hypothesis: If a light is shone at the Perspex, then the light will be refracted because of the shape of the Perspex, and because it is pasting through a medium. If the angle of incidence and refraction was measured and calculated the refracted index would be about 1.49, since the refractive index of a substance is always the same. Equipment: - Ray box - Power supply - Wires - Perspex prism - Paper - Ruler and protractor - Single slit slide - Quadruplet slits slide - 2 colored slides Method: 1.
Microbe Mission: SEM vs TEM Directions: Answer following questions. Choose best answer. Can have multiple answers. 1. How does a scanning electron microscope produce an image?
Laboratory report ascertaining the absolute Focal Length of a Convex Lens Aim: The intention of this Laboratory experiment is to determine, with safety and exactitude, the precise Focal Length of the given Convex Lens. By using the data recorded down with a vast number of analytical techniques in conjunction with the formula given for a thin lens ( 1f=1u+1 v ) Theory: By using the formula given for a thin lens and substituting my measurements into the formula the result should be an exact measurement of the focal length (10cm) or (20cm) depending on the convex lens provided for the experiment. However my hypothesis would show that the results recorded will be slightly fallacious, since the major difficulty is to judge at which screen position or lens position can form the sharpest image. I think a major source of error is the scientist in questions eyesight; one of the dependant variables. Subsequently the entire experiment would be completely dependable on what was seen as in focus and not in focus.
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.
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
The objective of this investigation is therefore to establish a relationship between the length of a cantilever and its deflection in the aforementioned situation, which may give some insight into the physics of cantilevers. Variables The independent variable in this investigation is the length of the cantilever in meters. This will be varied by changing the length of the yardstick functioning as a cantilever that extends over the edge of a table. It will be measured indirectly by measuring the length of the portion of the yardstick not in use and subtracting that from the entire length of the yardstick. The dependent variable in this investigation is the deflection of the cantilever in meters.