SESSION
2025-2026
PHYSICS INVESTIGATORY PROJECT ON
“To Investigate The Dependence Of Angle Of Deviation On Angle Of Incidence
Using A Hollow Prism Filled One By One, With Different Transparent Fluids ”
Name: Shubhrajit Saha
Class : 12
Section : B
Roll No - 60
CERTIFICATE
This is to certify that Subhrajit Saha of Class XII B of Aditya
Academy has successfully completed his Physics Project on the
Topic- “To Investigate The Dependence of Angle Of
Deviation On Angle Of Incidence Using A Hollow Prism Filled
One By One, With Different Transparent Fluids” for the term
2025-26
Sign of the Internal Examiner Sign of the External Examiner
Sign of Principal
ACKNOWLEDGEMENT
I, Subhrajit Saha of Class XII B, Aditya Academy, would like to express
my heartfelt gratitude for the golden opportunity to explore and
enhance my skills and imagination through the project titled:
“To Investigate the Dependence of Angle of Deviation on Angle of
Incidence Using a Hollow Prism Filled One by One with Different
Transparent Fluids.”
I am deeply thankful to the Almighty, my parents, friends, and
classmates, whose constant support and encouragement helped elevate
this project to the next level. Their belief in me was the driving force
behind every step of this journey.
INDEX
Sr. Sub-topic Page Number
No.:
1 Cover Page 1
2 Certificate 2
3 Acknowledgement 3
4 Index 4
5 Aim and Apparatus Required 5-6
6 Theory 7
7 Diagram 8-9
8 Observations 10-15
9 Conclusion 16
10 Precautions 17
11 Applications: 18
12 Bibliography 19
Aim/Objectives:
The aim of this project is to investigate dependence of
angle of deviation on angle of incidence using a hollow
prism filled one by one with different transparent fluids.
Hypothesis:
The hypothesis of this project is –
• The angle of deviation increases with increase in
angle of incidence.
• The angle of deviation does not depend on the
liquid used in the hollow prism for deviation.
Apparatus Required:
1. Hollow glass prism
2. Liquids like-
Carbon Disulphide Water Benzaldehyde
3. Bell pins
4. Stiff drawing board
Theory:
• A prism is a transparent optical object with flat,
polished surfaces that refract light. Prisms can be
made from any material that is transparent including
glass
and even plastic.
• 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= =
Where-
U=refractive index of the
liquid. a = angle of minimum
deviation d=angle of prism
i=angle of
incidence r=angle
of refraction
Diagrams:
Process:
• Fix a white sheet of paper on the drawing board
with help of pins.
• Keep the prism on the paper and draw its outline 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 below
• Repeat this with different liquids and different angle
of incidence.
Observations:
The following are the observation tables of each of
the liquids used to find out their respective
refractive indices-
Benzaldehyde:
Sr. No.: Angle of Angle of Angle of
prism incidence deviation
1. 60 30 45
2. 60 35 42
3. 60 37.5 40
4. 60 39 42
5. 60 40 45
U = = 1.504
Water:
Sr. No. Angle of Angle of Angle of
prism incidence deviation
1. 60 30 25
2. 60 35 22
3. 60 40 20
4. 60 45 22
5. 60 50 25
6. 60 55 28
U = = 1.306
Dilute Sulphuric Acid:
Sr. No. Angle of Angle of Angle of
prism incidence deviation
1. 60 20 33
2. 60 30 30
3. 60 35 25
4. 60 40 29
5. 60 45 30
U = = 1.351
Graphical representation of observations:
Conclusion:
The refractive indices change when the liquid used in the prism
changes. From the above experiment we can also
conclude that refractive index of a liquid depends on its optical density.
Refractive indices of the used liquids
obtained, when compared with the actual
values are as follows-
1. Benzal
dehyd
e:
Actual
=
1.5456
Obtained = 1.504 Deviation/Error
= 0.0416
2. Water:
Actual = 1.33 Obtained = 1.306
Deviation/Error = 0.024
3. Dil.
Sulphuric
Acid
Actual =
1.43
Obtained = 1.351 Deviation/Error
= 0.079
Analysis and
Interpretation:
From the observations above, we can analyze that the angle of
deviation is depending on the liquid present in the prismas, the
angle of deviation is different for Benzaldehyde, water and dilute
sulphuric acid at 30 (45 , 25 and 30 respectively).
We can also see that the angle of deviation does depend on the
angle of incidence, as when the angle of incidence is
changed the angle of deviation also changes.
The theoretical values of all the angle of deviations for all liquids
may vary due to different concentration and different prisms
being used for the experiment. The observations may also be
affected by the physical conditions like humidity and temperature of
surroundings.
Conclusions:
Comparing the conclusions to our initial hypothesis, we can say that
Our first hypothesis, i.e. “The angle of deviation increases with
increase in angle of incidence” is wrong as the angle of deviation
first decreases then increases with increase in angle of
incidence.
We can further conclude that our second hypothesis, i.e. ”The angle
of deviation does not depend on the liquid used in the hollow
prism for deviation” is also wrong.
Precautions:
Angle of incidence should be between 35 and 60
for better observations and accurate readings.
Pins should be vertically fixed and should not be
bent or damaged as reading can change.
Same hollow prism should be used for all
observations to minimize error due to prism.
Error or deviation in obtained refractive indices
must not be more than 0.1.
The distance between the pins should be
more than 10mm
Applications:
⇨ Refractive index has the large number of
applications. It is mostly applied for identify a
particular substance, confirm its purity, or
measure its concentration.
⇨ Generally it is used to measure the
concentration of a solute in an aqueous
solution. For a solution of sugar, the
refractive index can be used to determine the
sugar content.
⇨ It can be used to determine the drug
concentration in pharmaceutical industry.
⇨ It is used to calculate focus power of
lenses and dispersing power of prisms.
Bibliography:
https://studylib.net/doc/25306864/dlscrib.com
-hollow- prism-physics-investigatory-project-cl
http://www.refractometer.pl/refraction-datasheet-
sulfuric- acid
https://pubs.acs.org/doi/10.1021/jp0310145#:~:text=
The
%20refractive%20index%20of%20water%20is%20obta
ined
%20from%20the%20displacement,at%20633%20nm%
3B
%201.331%2058.
https://www.scribd.com/document/442279835/PROJECT
-ON- REFRACTIVE-INDEX-OF-DIFFERENT-LIQUIDS
