PHYSICS PRACTICAL
SHREE AMARSINGH MODEL HIGHER SECONDARY
SCHOOL, RAMGHAT POKHARA-12
PROJECT WORK OF 2070 BS
Submitted By:-
Submitted To:-
Ishwor Koirala
Mr. Baburam Sharma
Class:-XI ‘A’
Mr. Ramesh Chandra Tripathi
Roll No:-13
Physics practical
Date of Experiment:2070/11/06
TABLE OF CONTENTS
S.N.
ACTIVITY
PAGE
NO.
1
DETERMINATION OF SIZE AND
NATURE OF IMAGE FORMED BY
CONVEX LENS
4-7
2
VERIFICATION OF EXPANSION OF
LIQUID
8-10
3
VERIFICATION OF THE BERNOULLIS
PRINCIPLE
11-14
Signature: … … … … … … … … … …
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Physics practical
NOTATIONS USED
P = Static pressure of the fluid at the cross section
ρ = density of the flowing liquid
g = acceleration due to gravity
v = mean velocity of fluid flowing at the cross section
h = elevation head of the centre of cross-section
F = focus of lens
2F = centre of curvature of lens
O = optical centre of lens
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Physics practical
Activity No. 1
TITLE: - DETERMINATION OF SIZE AND NATURE OF IMAGE
FORMED BY CONVEX LENS.
OBJECT: - TO STUDY THE NATURE AND SIZE OF IMAGE FORMED
BY CONVEX LENS USING CANDLE AND A SCREEN.
APPARATUS REQUIRED
i.
ii.
iii.
iv.
Optical Bench
Candle
Convex Lens
Screen
THEORY
The image of an object formed by convex lens depends upon the
position of object with respect to the lens. The image produced by a
convex lens can be draw by using the following rules:
a) A ray passing through the optical center of the lens passes without
deviation.
b) A ray parallel to the principal axis passes through focus after
refraction.
c) A ray passing through the focus emerges parallel to the principal
axis after refraction.
PROCEDURE:
An optical bench was taken and candle and paper as screen were
placed. In between them, a convex lens was placed. Then:
a) The candle was lit and used as an object.
b) The lens was kept at a distance from the object.
c) A screen was used to observe the image formed by the lens.
d) The distance was changed and the same other procedures were
repeated.
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Physics practical
OBSERVATION:
Following images were produced by lenses at different distances:
At infinity:
Beyond 2F:
At 2F:
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Physics practical
Between 2F and F:
At F:
S.N
Position of
object
Position of Nature of
image
image
At infinity
At focus
Real & Inverted Extremely
small
Between infinity
and 2F
Between F
& 2F
Real & Inverted Small
III.
At 2F
At 2F
Real & Inverted Same size
IV.
Between 2F and F
Beyond 2F
Real & Inverted Magnified
I.
II.
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Size of
image
Physics practical
V.
At focus(F)
At infinity
Real & Inverted Extremely
large
RESULT:
From the activity, the image formed by the convex lens was found to be
real and inverted and increased in size while moving from infinity to
optical center.
CONCLUSION:
From the activity it could be concluded that, convex lens forms real
and inverted image but image of object between F and O can’t be
observed since the image was virtual.
BIBLIOGRAPHY
1. Fundamentals of Physics ( Devi Dutta Paudyal,
Udayaraj Khanal, Sitaram P. Byahut, Shankar Saran
Karki).
Principles of Physics ( Manu Kumar Khatry, Manoj Kumar Thapa,
Bhesha Raj Adhikari, Arjun kumar Gautam, Parashu Ram Poudel)
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Physics practical
Activity No 2
TITLE: - VERIFICATION OF EXPANSION OF LIQUID.
OBJECT: - TO REALISE AND STUDY THE REAL EXPANSION OF
LIQUID IN A VESSEL.
APPARATUS REQUIRED
i. Vessel fitted with glass tube of small diameter.
ii. Stand
iii.Burner
iv. Experimental Liquid.
THEORY
Liquid cannot be heated directly. To heat the liquid a vessel is required.
When the liquid is heated in the vessel, the liquid as well as vessel get expand.
The expansion of liquid that we realize in the vessel is called apparent
expansion which is different from the real expansion of the liquid. To obtain the
real expansion of liquid the cubical expansion of vessel is also taken into
account along with the apparent expansion of the liquid.
To realize the real expansion of the liquid, consider a vessel having narrow
long stem in which initially liquid is filled up to mark A. Now the liquid is
heated in the vessel. First of all the vessel gets expand and to fill up the
expanded space the liquid level falls to mark AB volume is the cubical
expansion of liquid. When the liquid gets heat liquid level rises from mark B to
mark C. AC volume is the apparent expansion of liquid. In the figure BC = AB
+ AC, is the real expansion of liquid, AB is the cubical expansion of vessel and
AC is the apparent expansion of liquid.
PROCEDURE
1. Take a vessel filled with water.
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Physics practical
2. Fit a cork and connect it with thin glass tube to close the mouth of
vessel.
3. Put the vessel inside another big vessel and fit it in a stand as shown
in the figure.
4. Pour some water in the vessel and heat it with the help of Bunsen
burner.
OBSERVATIONS
Initial height of liquid = 25cm
Height of the liquid on second reading = 23.8cm
Final reading of height of liquid = 36.4cm
Now,
Cubical expansion of vessel = Initial height – Second reading of height
= 25cm – 23.8cm
= 1.2cm
Apparent expansion of liquid = Final height – Initial height
= 36.4cm – 25cm
= 11.4cm
Real expansion of liquid = Cubical expansion + Apparent expansion
= 1.2cm + 11.4cm
= 12.6cm
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Physics practical
ANALYSIS OF THE EXPERIMENT
Here we observed that the water at point A is gradually decreased to point
B. This is due to the expansion of the vessel by heating. But after some time due
to the expansion of the water, the water level rises to point C.
CONCLUSION
From the above experiment we concluded that the liquids have expanded
by absorbing heat. If we heat the vessel more, then the water level in the vessel
will be increased and the temperature will also be increased. So the volume of
water is increased if the temperature is increased i.e. the volume of the liquid is
directly proportional to temperature.
BIBLIOGRAPHY
1. Fundamentals of Physics ( Devi Dutta Paudyal, Udayaraj
Khanal, Sitaram P. Byahut, Shankar Saran Karki).
2. Principles of Physics ( Manu Kumar Khatry, Manoj Kumar
Thapa, Bhesha Raj Adhikari, Arjun kumar Gautam, Parashu
Ram Poudel)
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Physics practical
Activity No. 3
TITLE: - VERIFICATION OF THE BERNOULLIS PRINCIPLE.
OBJECT: - TO STUDY THE VARIATION OF AIR PRESSURE WITH
RESPECT TO CHANGE IN VELOCITY OF AIR.
APPARATUS REQUIRED
i.
ii.
iii.
Long rod
Two balloons of same size.
Thread
THEORY
Bernoulli’s principle states that “For the streamline flow of an ideal liquid
the total energy per unit mass
remains constant throughout
the flow.”
Suppose an
incompressible fluid flows
through a pipe of non uniform
cross- section as shown in the
diagram. Let us consider two
sections of area A1 and A2 of
the pipe which are at different
heights h1 and h2 respectively
from a reference level.
Assume that the velocities of the fluid at those sections are v1 and v2
respectively and corresponding values of pressure are P1 and P2 respectively.
The volume of the fluid passing a small interval of time dt through both the
sections will be same and is equal to
A1V1dt = A2V2dt
(From continuity equation)
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Physics practical
or, A1ds1 = A2ds2 = dV,
Where ds1 and ds2 are the displacement of the fluid of the corresponding
sections.
Net work done on the fluid element by its surrounding fluid will be,
dW = Work done at section 1 + Work done at section 2
= (Force × displacement)1 + (Force × displacement)2
= P1A1× ds1 + (-P2A2 × ds2) [negative sign is due to opposite
pressure at 2 section]
nd
= (P1-P2)A1ds1
dW = (P1-P2)dV ……….. (i)
Here we have neglected the viscosity of the fluid.
This work done must increase the mechanical energy of the fluid. Net increase
in kinetic energy (T)
dT = Kinetic energy at second section – kinetic energy at first section
= ½ (ρdV)v22 – ½ (ρdV)v12
or, dT = ½ ρdV(v22- v12)……………(ii)
Here ρ is the density of the liquid.
Similarly net increase in gravitational potential energy (U),
dU = (ρdV)gh2 - (ρdV)gh1
or, dU = (ρdV)g(h2 – h1)………….(iii)
From the principle of conservation of energy applied for mechanical energy, we
must have,
Work done on a system = increase in its mechanical energy.
Therefore, dW = dU + dT ………… (iv)
Substituting (i), (ii), (iii) in (iv)
(P1 – P2)dV =½ρdV(v22- v12) + ρdVg(h2 – h1)
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or,P1 + ρgh1 + ½ρ v12 = P2 + ρgh2 +½ρv22
This Equation is known as Bernoulli’s Equation. It can also be written as
P + ρgh + ½ρv2 = constant.
When air is blown into two suspended balloon with a small distance between
them, the velocity of the air in the gap between them increases.
According to the Bernoulli’s theorem due to increase in the velocity of
the air in the gap between them increases the pressure gets considerably
lowered. But the air on the balloon being the atmospheric pressure is now very
larger than the pressure in the gap The difference in the pressure results in the
striking of the two balloons.
PROCEDURE
First two balloons of equal sizes are blown with air and suspended
at two ends of a rod separated by a small distance with the help of thread. The
rod held free in one hand. Then, air is continuously blown just in between the
two balloons for sometime.
OBSERVATION AND RESULT
It was observed that slowly the balloons begin to move towards
each other and strike with one another.
ANALYSIS OF MOVEMENT
According to the Bernoulli’s Principle
P +½ρv2 = constant
Where ρ is density, P is pressure and v is the velocity.
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Physics practical
When air is blown in
between the two
suspended balloon, the
velocity of air in between
the balloons is increased.
As a result, the pressure
between the balloons
decreases but the pressure
outside the balloon being
atmospheric pressure is
higher. Hence the balloons
at higher pressure zone tend to move towards the low pressure zone which
results of the two balloons moving closer to one another which ultimately
results to striking of the balloons. The same experiments can be done with two
apples.
CONCLUSION
In this way, Bernoulli’s principle was verified by using two balloons.
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