Hollow Prism - Physics Investigatory Project Class 12 CBSE

KENDRIYA VIDYALAYA No. 2, Pondicherry University Campus, Kalapet, Puducherry-14 PHYSICS INVESTIGATORY PROJECT 2013-‘14 DETERMINATION OF REFRACTIVE INDICES OF VARIOUS LIQUIDS USING A HOLLOW PRISM

Guided by,

Submitted by, Class XII

BONA FIDE CERTIFICATE It is hereby to certify that, the original and genuine investigation work has been carried out to investigate about the subject matter and the related data collection and investigation has been completed solely, sincerely and satisfactorily done by NAME of Class XII, Kendriya Vidyalaya No.2, Pondicherry-14, regarding the project titled, “REFRACTIVE INDICES OF VARIOUS MEDIUMS” Signature of the Guide

Principal’s Signature

Submitted for ALL India SENIOR SECONDARY EXAMINATION held on _____________ at KENDRIYA VIDYALAYA No.2, PONDICHERRY.

Internal Examiner

External Examiner

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 her valuable support, constant help and guidance at each and every stage, without which this project would not have come forth. I also register my sense of gratitude to our principal, Mr.principal, for his immense encouragement that has made this project successful. I would also like to thank my friends and family for encouraging me during the course of this project. 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, carbon disulphide, benzaldehyde etc.  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  Benzaldehyde 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

30 35 37.5 39 40

45 42 40 42 45

U=sin((60+40)/2)/sin(30) = 1.504  Water S.no

a º(angle of prism) i º (angle of incidence) d º (angle of deviation)

1 2 3 4 5 6

60 60 60 60 60 60

30 35 40 45 50 55

U=sin((60+22)/2)/sin(30) = 1.306

25 22 20 22 25 28

 Dil. Sulphuric Acid 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+25)/2)/sin(30) = 1.351

33 30 25 29 30

Conclusion Refractive indices at room temperature:  Benzaldehyde o Actual: 1.546 o Experimental: 1.504 o  Water o Actual: 1.33 o Experimental: 1.306 o  Dil . Sulphuric acid o Actual: 1.355 o Experimental: 1.351

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.