ARMY PUBLICSCHOOL DANAPUR CANTT PHYSICS INVESTIGATORY PROJECT SESSION :- 2015-2016 TOPIC:-To find out the refractive indices of different liquids using a hollow prism SUBMITTED BY:GUIDED BY:GAURAV BAMAN XII SCI ‘A’ ROLL NO - DATE : TEACHER’S SIGNATURE EXAMINER’S SIGNATURE : : .CERTIFICATE THIS IS TO CERTIFY THAT GAURAV BAMAN 0F CLASS XII SCI ‘A’ HAS SUCCESSFULLY COMPLETED HIS INSSVESTIGATORY PROJECT WORK OF PHYSICS FOR CLASS 12 PRACTICAL EXAMINATION OF CENTRAL BOARD OF SECONDARY EDUCATION IN YEAR 2015-16. THANKS . GUIDANCE AND ENCOURAGEMENT WITHOUT WHICH THIS PROJECT WOULD HAVE NOT COME FORTH.ACKNOWLEDGEMENT I WOULD LIKE TO EXPRESS MY SINCEERE GRATITUDE TO MY PHYSICS MENTOR .MR. I WOULD LIKE TO EXPRESS MY IMENSE GRATITUDE TO THE LAB ASSISTANT MR SANTOSH FOR HIS KIND SUPPORT DURING THE MAKING OF THIS PROJECT. PK SAMANTRAY FOR HIS VITAL SUPPORT. Project Overview Aim Apparatus Required Theory Procedure Observations Conclusions Precautions . benzaldehyde etc.Bibliography Aim To find out the refractive indices of different liquids using a hollow prism Apparatus Required Hollow glass prism Various liquids like water. carbon disulphide. Bell pins Drawing board . The refractive index of the liquid Is given by the formula: U=sin(i)/sin(r)=sin((a+d)/2)/sin(a/2) Where. a= the angle of minimum deviation d=angle of prism i=angle of incidence . Prisms can be made from any material that is transparent including glass. U=refractive index of the liquid. A prism can be used to break light up into its constituent spectral colours. Prisms can also be used to reflect light. or to split light into components with different polarizations.Theory A prism is a transparent optical element with flat. plastic and fluorite. polished surfaces that refract light. Remove the prism and draw the line joining the points so obtained. Mark the diagram as shown in the figure.r=angle of refraction Procedure 1. Place the prism filled with given sample of liquid on the marked outline ABC. 7. Now take the pins and place them on the side AC so that all the 4 pins appear to be in same line. 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. . 2. 4. Fix a white sheet of paper on the drawing board with help of drawing pins. Drop a normal PQ on the side AB. Keep the prism and mark the outline of it as ABC. 6. 5. 3. 8. Observation Benzaldehyde S.no a º(angle of prism) 1 2 3 4 5 60 60 60 60 60 i º (angle of incidence) 30 35 37.no 1 2 3 4 5 6 a º(angle of pri i º (angle of incidence) d º (angle of deviation) sm) 60 60 60 60 60 60 30 35 40 45 50 55 25 22 20 22 25 28 . Repeat this with different liquids and different angle of incidence.504 s.5 39 40 d º (angle of deviation) 45 42 40 42 45 U = sin ((60+40)/2)/sin(30) = 1.9. Sulphuric Acid S.306 Dil.351 d º (angle of deviation) 33 30 25 29 30 .no 1 2 3 4 5 a º(angle of prism) 60 60 60 60 60 i º (angle of incidence) 20 30 35 40 45 U = sin((60+25)/2)/sin(30) = 1.U = sin ((60+22)/2)/sin(30) = 1. 546 Experiment = 1.Conclusion Refractive indices at room temperature: Benzaldehyde Actual = 1.504 Water Actual = 1. Sulphuric acid Actual = 1.351 .33 Experiment = 1.306 Dil.355 Expweriment = 1. Arrow head should be marked to represent emergent and incident ray. 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.Precautions Angle of incidence should lie b/w 3560 degree.