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.