THE NEW TULIP INTERNATIONAL SCHOOL Sterling City, Bopal, Ahmedabad, Gujarat PHYSICS INVESTIGATORY PROJECT 2018-19 DETERMINATION OF REFRACTIVE INDICES OF VARIOUS LIQUIDS USING A HOLLOW PRISM Guided by, Submitted by, Sanskar Nalkande Class XII Certificate This is to certify that Sanskar Nalkande of class XII-F has completed the physics project titled ‘Determination of refractive indices of various liquids, using a hollow prism’ under the guidance of his physics teacher. The progress of the project has been continuously reported and has been acknowledged consistently ACKNOWLEDGEMENT The successful completion of any task would be incomplete without mentioning the names of those persons who helped to make it possible. I take this opportunity to express my gratitude in few words and respect to all those who helped me in the completion of this project. It is my humble pleasure to acknowledge my deep senses of gratitude to my Physics teacher, Teacher name for his valuable support, constant help and guidance at each and every stage, without which this project would not have come forth. Last, but not the least, I would like to thank CBSE for giving us the opportunity to undertake this project. Project Overview Aim Apparatus Required Theory Procedure Observations Conclusions Precautions Bibliography Aim To find out the refractive indices of different liquids using a hollow prism Apparatus Required Hollow glass prism Various liquids like water, glycerin, coconut oil Bell pins Drawing board Theory A prism is a transparent optical element with flat, polished surfaces that refract light. Prisms can be made from any material that is transparent including glass, plastic and fluorite. A prism can be used to break light up into its constituent spectral colors. Prisms can also be used to reflect light, or to split light into components with different polarizations. The refractive index of the liquid Is given by the formula: U=sini/sinr=sin((a+d)/2)/sin(a/2) Where, U=refractive index of the liquid. a= the angle of minimum deviation d=angle of prism i=angle of incidence r=angle of refraction Procedure Fix a white sheet of paper on the drawing board with help of drawing pins. Keep the prism and mark the outline of it as ABC. Drop a normal PQ on the side AB. Draw the angle of incidence in accordance with the normal PQ and place 2 pins so that they appear to be in the straight line. Place the prism filled with given sample of liquid ,on the marked outline ABC. Now take the pins and place them on the side AC so that all the 4 pins appear to be in same line. Remove the prism and draw the line joining the points so obtained. Mark the diagram as shown in the figure. Repeat this with different liquids and different angle of incidence. Observation Glycerin S.no a º(angle of prism) i º (angle of incidence) d º (angle of deviation) 1 2 3 4 60 60 60 60 30 40 45 60 40 45 40 37 U=sin((60+35)/2)/sin(30) = 1.47 Water S.no a º(angle of prism) i º (angle of incidence) d º (angle of deviation) 1 2 3 4 60 60 60 60 30 45 60 65 U=sin((60+23)/2)/sin(30) = 1.325 25 36 26 30 Coconut Oil S.no a º(angle of prism) i º (angle of incidence) d º (angle of deviation) 1 2 3 4 5 60 60 60 60 60 20 30 35 40 45 U=sin((60+33)/2)/sin(30) = 1.449 33 30 25 29 30 Conclusion Refractive indices at room temperature: Glycerin o Actual: o Experimental: Water o Actual: o Experimental: Coconut oil o Actual: o Experimental: 1.473 1.47 1.33 1.325 1.453 1.449 Precautions Angle of incidence should lie b/w 35- 60 degree. Pins should be vertically fixed and should lie in same line. Distance b/w two points should not be less than 10mm. Same angle of prism should be used for all observation. Arrow head should be marked to represent emergent and incident ray.