# What effects displacement of a ray of light?

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Introduction

Investigation: What effects displacement of a ray of light? Variables * The angle the light hits the block at * The width of the block * The colour of the light * Light intensity Predictions * The larger the angle the larger the displacement. (See Diagram) In the diagram I have used snell's law to find the refracted angle, Snell's law is that for glass Sin i Sin r = 1.5 By using this I have been able to work out accurate results without doing an experiment. * The displacement will be directly proportional to the width of the block. I.e. The wider the block the larger the displacement E.g. if you double the thickness of the block then the displacement will double (See Diagram) Plan 1 The apparatus that I need for the experiment is 1 Protractor 2 Ray Box 3 Ruler 4 Blank page 5 Glass block 6 Power Pack The measurements to be taken are: the size of the blocks : The size ...read more.

Middle

Accurate results will be acquired by checking results with another member of the group who carried out the same investigation and then taking the average of the two results A two millimetre margin of error for the displacement will be allowed because there could be inaccuracy in the measurement of the displacement and block, and the block may have been sitting in a slightly different position to the one it was drawn in. I choose 2mm because I felt that if it was anymore the results would become inaccurate. I will collect my results in a table Width of block (cm) Reading 1 (cm) Reading 2 (cm) Average (cm) Then I will put these results into a graph Displacement (cm) Width of block (cm) From my prediction I expect my graph to have the same shape as shown above. Results Table Angle of Incidence = 48 degrees Width of Block Reading 1 Reading 2 Average 6.3cm 1.9cm 2.1cm 2cm 8.2cm 2.5cm 2.5cm 2.5cm 12.7cm 3.7cm 4.1cm 3.9cm ...read more.

Conclusion

The ray was too thick; if repeating the experiment I could do it with a thinner and stronger ray, so I could get an exact result instead of an approximate one. After considering all these I allowed 2mm either side of the point for measuring the displacement, as seen on the graph. If I were repeating the experiment again then I would make sure that I had a stronger and thinner light ray. Also a more accurate way of measuring the displacement and the length of the blocks. I would take three or four readings for each thickness to make sure that I had very accurate results and this would hopefully lead to an overall improvement in my results. I used an angle of incidence of 42 degrees, so I can work out the refracted angle by using: Sin I 1.5 =sin r Sin 42 1.5 =26.5 degrees So the angle of incidence is 26.5 degrees. ...read more.

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