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Imam Mohammed bin Saud University
Science Collage
GENERAL PHYSICS
LAB MANUAL
Physics Lab
Science Collage-Imam University
Physics 101
Lab
2
 General physics course is mainly about mechanics
and electricity. You will perform basic
experiments.
 Hope you enjoy your physics lab ….
Physics Lab
Science Collage-Imam University
physics
Lab Rules
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All students must attend the lab section.
No food. No drinks.
The lab must be clean at all time.
Ask your teacher to check all electrical circuits
before turning on the power supply.
Before making any adjustments on your
electrical circuit make sure it is turned off.
At the end of each lab switch off and unplug any
electrical equipment and disconnect all circuits
and arrange all equipment tidily on the bench.
Lab reports must be submitted in a week’s time.
Lab reports writing must be an individual effort
although the experiments will be performed in
groups.
The lab is worth 20% of the course’s grade.
A missed lab will receive a zero grade.
A make up lab must be performed during the
same week of the missed lab if your instructor
accepts your excuse.
Physics Lab
Science Collage-Imam University
Lab report
guide
4
Your lab report should consist of:
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Title Page :
The following information must appear all by itself on the
first page:
the title of the experiment
your name
the names of your partners, if any
the performance date
the course and section numbers
the name of your Lab Instructor
Introduction:
Objective, method and results.
Experimental procedure:
Description of apparatus and outline of technique.
Discussion uoy woh nialpxe ,atad ruoy tneserp uoy ereH :
tcelfer dna ,EVITCEJBO eht rof eulav a ot atad ruoy decuder
.tluser ruoy fo ytilibailer eht no
Data summary ni ,ereh atad war detcelloc eht tneserP :
ni dedulcni eb dluohs detaerc uoy shparg ynA .mrof ralubat
laiceps no nward eb dluohs shparG .osla ,noitces siht
dna selbat ,shparG .gnilacs etairporppa htiw repap gnihparg
.snoitpac dna seltit elbigel evah tsum serugif
Physics Lab
Science Collage-Imam University
Lab report
guide
5
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Analysis: lacitamehtam eht ,hpargarap eno ni ,ebircseD
eulav lanif eht otni atad war eht trevnoc ot desu spets
eht rof detroper objective.
Errors: ycarucca eht no tnemmoc hpargarap elgnis a nI
fo noissucsid a edulcni dna sutarappa eht fo noisicerp dna
ruoy ni rorre eht fo etamitse na dna srorre latnemirepxe eht
.tluser lanif
The two principal sources or error are:
Physical phenomena similar to the phenomena being
measured that affect the measured quantity (e.g., stray
magnetic or electric fields, unaccounted for friction).
Limitations of the observer, the analysis and/or the
instruments.
Conclusion eht gnidulcni ,stluser ruoy etatseR :
tluser ruoy erapmoC .stluser laciremun yna ni ytniatrecnu
.eulav detpecca eht htiw
Appendices snoitseuq ot srewsna eht ereh edulcnI :
ni derewsna eb dluohs yehT .launam bal eht morf dengissa
.ygolonimret cifitneics etairporppa gnisu secnetnes etelpmoc
Physics Lab
Science Collage-Imam University
Experiment 1
Balancing force (force table)
6
 Objective:
Using the force table to experimentally find the
balancing force of two forces.
 Theory:
Forces are vector quantities which have both
magnitudes and directions.
An object with different forces acting on it is
considered in equilibrium when the vector sum of all
individual forces acting on it is zero, or in other
words when the resultant force acting on the object
is equal to zero.

F  0
F
x
0
F
y
Physics Lab
Science Collage-Imam University
0
Experiment 1
Continued
7
An object moving as a result of different forces can
be balanced by an equilibrant force which is equal
and opposite of the resultant force of all forces
acting on it.


FR   FE
Where FR is the resultant force and FE is the
equilibrant force.
Physics Lab
Science Collage-Imam University
Experiment 1
Continued
8
There are two methods to fond the resultant force of
two forces graphically:
1- Tip to Tail Method:
We can add any two forces, F1 and F2, by placing the
tail of F2 so that it meets the tip of F1.
The sum, F1 + F2, is the vector from the tail of F1 to
the tip of F2.
F2
F1
FR
Note that you’ll get the same vector if you place the
tip of F2 against the tail of F1. In other words, F1 +
F2 and F2 + F1 are equivalent.
Physics Lab
Science Collage-Imam University
Experiment 1
Continued
9
2- Parallelogram Method:
To add F1 and F2 using the parallelogram method,
place the tail of F2 so that it meets the tail of F1.
Take these two forces to be the first two adjacent
sides of a parallelogram, and draw in the remaining
two sides. The vector sum, F1 + F2, extends from the
tails of F1 and F2 across the diagonal to the opposite
corner of the parallelogram.
F1
FR
F2
Physics Lab
Science Collage-Imam University
Experiment 1
Continued
10
 Equipment:
Force table – stand base – pulleys – hangers –
weights (slotted masses) – strings – center ring –
protractor .
Physics Lab
Science Collage-Imam University
Experiment 1
Continued
11
The force table is a circular table that has the angles
0 degrees to 360 degrees inscribed on the edge.
Pulleys are placed at different angles with strings
attached to a center ring running over the pulleys.
Masses are placed on mass hangers attached to the
end of the strings to provide the forces needed.
By adding the vectors (applied forces), the resultant
vector is found. To balance the force table, a force
that is equal in magnitude and opposite in direction
must counterbalance the resultant. This force is the
equilibrant force.
Physics Lab
Science Collage-Imam University
Experiment 1
Continued
12
 Procedure:
1- Your lab instructor will provide you with two
different forces (magnitude and direction). Attach
suitable slotted masses with the thin strings to the
center ring of the force table.
Remember that:
F1=M1g
and
F2=M2g
where g=9.8
m/s2 which is the gravitational acceleration.
2- Consider the direction of each force which is
represented by the angle. The force table’s edge will
help you identify the angle accurately.
3- In order to balance the ring; a third force should
be attached.
Physics Lab
Science Collage-Imam University
Experiment 1
Continued
13
4- Record the magnitude and direction of the
equilibrium force.
5- Plot both original forces on graphing paper by
setting a drawing scale (1 cm = 1 N).
6- Find the resultant force graphically. The
magnitude of the force is represented by the length
of the vector and should be converted using the scale
you have chosen. The direction is represented by the
angle which you can measure using the protractor.
7- Now find the equilibrant force which is equal and
opposite to the resultant force.
8- Record all values in the following table.
9- Find the percentage error.
Physics Lab
Science Collage-Imam University
Experiment 1
Continued
14
 Data:
Force 1
Force 2
Percentage
error
Balancing force
graphically
experimentally
Magnitude
Angle
 Percentage Error:
PE 
Re alValue  ExperimentalValue
Physics Lab
Science Collage-Imam University
Re alValue
x100
Experiment 2
Acceleration of Linear uniform motion
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 Objective:
To calculate the acceleration of an object moving in
a straight line with a constant acceleration using
equations of motion.
 Theory:
Equations of motion are used to study the linear motion of
a uniformly accelerated body.
1 2
d  v 0 t  at
2
v f  v 0  at
where:
d:
v f2  v 02  2ad
Displacement or change in position
vf:
Original velocity, the velocity at the start of
the acceleration
Final velocity, the velocity at the end of the
acceleration.
a:
Acceleration, this is a constant acceleration
t:
Time, this is the time period of the
acceleration.
vo:
Physics Lab
Science Collage-Imam University
Experiment 2
Continued
16
 Equipment:
Track – trolley – holding magnet – electronic stop
clock – light barrier – pulley – mass hanger –
slotted weights – cables.
Physics Lab
Science Collage-Imam University
Experiment 2
Continued
17
 Procedure:
1- Set the equipment, use the cable to connect the trolley
with the pulley and the hanging mass.
2- You can perform this experiment by using either one or
two light barriers.
3- If you are using a holding magnet and one light barrier.
Connect the holding magnet to the stop clock and adjust
the voltage so that the trolley is held.
4- Put the light barrier at a certain distance.
5- Release the trolley by stopping the magnet and record the
time the trolley took to pass the light barrier.
6- Repeat and record the time three times then calculate the
average time and the final velocity.
7- Change the distance and repeat the previous steps for
each distance.
8- If you are using two light barriers, place each barrier at
certain distance and hold the cart at the first barrier then
release it and record the time.
Physics Lab
Science Collage-Imam University
Experiment 2
Continued
18
9- Repeat and record the time three times then calculate the
average time and the final velocity.
10- Change the distance and repeat the previous steps for
each distance.
11- Whether you used one or two light barriers, tabulate
your data.
Distance
m
Time 1
s
Physics Lab
Science Collage-Imam University
Time 2
s
Time 3
s
Average
Time
s
Time
square
s2
Experiment 2
Continued
19
12- Plot a graph between the square time (x-axis) and
the distance (y-axis).
13- Draw the best line and find its slope at each graph.
14- Calculate the acceleration from each slope using
equations of motion.
15- Find the real value of the carts acceleration using
Newton’s second law which states that the force is
proportional to the acceleration. F=ma where F
could be found from the mass causing the motion of
the cart.
16- Find the percentage error of the acceleration.
PE 
Re alValue  ExperimentalValue
Physics Lab
Science Collage-Imam University
Re alValue
x100
Experiment 3
Free fall
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 Objective:
To calculate the gravitational acceleration of free
falling ball.
 Theory:
Under free fall all objects have the same constant
acceleration, which in metric system is equal to 9.8 m/s2
at sea level. Equations that describe free fall are:
1
Δy  v 0 t  gt 2
2
v f  v 0  gt
v f2  v 02  2g Δy
where:
Δy:
vo:
vf:
g:
t:
Vertical displacement
Original velocity, the velocity at
the start of the acceleration
Final velocity, the velocity at the
end of the acceleration.
Acceleration due to gravity
Time, this is the time period of
the acceleration.
Physics Lab
Science Collage-Imam University
Experiment 3
Continued
21
 Equipment:
Steel ball – contact plate – holding magnet –
holding magnet adapter with a release mechanism –
electronic stop clock – stand base – rods – scale –
connecting leads.
Physics Lab
Science Collage-Imam University
Experiment 3
Continued
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 Procedure:
1- Set the equipment and hold the steel ball using the
holding magnet at a certain height.
2- Release the ball and read the time the ball took
traveling the vertical distance, then reset the stop
clock and reattach the ball and read the time again ,
you should take three readings of the time then find
the average time the ball has traveled.
3- Reduce the height and repeat the previous steps.
4- Tabulate your data.
Height
m
Time 1
s
Physics Lab
Science Collage-Imam University
Time 2
s
Time 3
s
Average
Time
s
Time square
s2
Experiment 3
Continued
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5- Plot a graph between the square time (x-axis) and
the height (y-axis) or displacement of ball.
6- Draw the best line and find its slope.
7- Calculate the gravitational acceleration from the
slope using equations of free fall.
8- Find the percentage error.
PE 
Re alValue  ExperimentalValue
Re alValue
x100
9- Repeat the previous steps using a different mass
ball.
10- State your observation
Physics Lab
Science Collage-Imam University
Experiment 4
Conservation of mechanical energy
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 Objective:
To find the final velocity of an object sliding an
incline with constant acceleration using energy
conservation law.
 Theory:
Energy is the ability to do work and is measured by
Jouls. Mechanical energy has two different forms:
Potential energy is the energy an object stores due
to its position.
The gravitational potential energy is given by:
PE = m g h
Where m is the mass of the object, g is the
gravitational acceleration and h is the height of the
object.
Kinetic energy is the energy of motion.
The kinetic energy is given by:
KE = (1/2) m v2
Physics Lab
Science Collage-Imam University
Experiment 4
Continued
25
The total mechanical energy E, of any isolated
system of objects, is defined as the sum of the kinetic
and potential energies:
E = PE + KE
The principle of conservation of energy could be
written as:
Ei = Ef
Where Ei is the initial energy and Ef is the final
energy
An object on an incline will move down with
constant acceleration. Energy conservation law:
Ei = Ef
KEi + PEi = KEf + PEf
Physics Lab
Science Collage-Imam University
Experiment 4
Continued
26
)1/2(m vi fh g m +2 fv m )1/2( = ih g m +2
If the object starts from rest, we get:
m g hi = (fh g m +2 fv m )1/2
)1/2(m vf – ih g m =2 m g hf
)1/2(vf – ih g =2 g hf
vf  2g(h i  h f )
From the equations of motion:
d = (t )fv + iv( )1/2
If the object starts at rest, we get:
vf = 2d / t
Which means that the final velocity could be found
either by the energy conservation law or by equation
of motion .
Physics Lab
Science Collage-Imam University
Experiment 4
Continued
27
 Equipment:
Track – trolley – holding magnet – electronic stop
clock – light barrier – cables.
Physics Lab
Science Collage-Imam University
Experiment 4
Continued
28
 Procedure:
1- Set the track so that it will become an incline by
rising one side of it, use the holding magnet to hold
the trolley still.
2- Connect the stop clock with a light barrier and put
the light barrier at a certain distance and record the
distance that the trolley should travel.
3- Measure the height at the beginning and at the
end of the motion of the trolley.
4- Release the trolley and find the time it needs to
travel the distance three times and find the average
time of traveling.
5- Use the equations to find the final velocity. The
two values should be equal.
6- Find the percentage error.
7- Calculate the initial and final PE and KE.
8- Repeat the previous steps by changing the height,
the mass and the distance and conclude their effect
on energy.
Physics Lab
Science Collage-Imam University
Experiment 5
Ohm’s Law
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 Objective:
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To test Ohm’s law by plotting V versus I to
determine the value of a resistor.
To calculate the equivalent resistance of two
resistors in series.
To calculate the equivalent resistance of two
resistors in paralle.
 Theory:
When a constant potential difference ,ΔV ,is applied
to a conducting material, a current density, J, is
established that is directly proportional to the
electric field, E, created within the material. The
constant of proportionality is known as the
electrical conductivity ,σ and the relation is known
as Ohm's Law :
J =σ E
Physics Lab
Science Collage-Imam University
Experiment 5
Continued
30
The electric field created by the potential difference,
establishes a current, I, in the conductor which is
directly proportional to the potential difference. By
considering the resistance of a given length of
material, a more useful and familiar form of Ohm's
Law may be derived:
ΔV=IR
where the constant of proportionality, R, is the
resistance of the conductor. where the unit of
resistance, ohm.
Some materials resist current very little while
others resist current almost completely. In general,
the resistance of a material depends on the applied
voltage.
Physics Lab
Science Collage-Imam University
Experiment 5
Continued
31
In an electrical circuit, a combination of resistors
can be connected as in parallel or in series .
The equivalent resistance, R, for the resistors in
series is given by
R=R2R+1
R2
R1
The equivalent resistance, R, for the resistors in
parallel is given by
1/R = (1/R1)+(1/R2)
R1
R2
Physics Lab
Science Collage-Imam University
Experiment 5
Continued
32
The following chart summarizes the relation
between different variables related to Ohm’s law.
 Equipment:
DC power supply –Ammeter –Voltmeter –
breadboard - resistors –connecting leads.
Instead of using ammeters and voltmeters; digital or
analog ‫و‬multimeters could be used.
Physics Lab
Science Collage-Imam University
Experiment 5
Continued
33
 Procedure:

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Part A:
Connect the circuit as in the following figure:
For each resistance write first the real value
then change the voltage V and read the current
I, then insert all data in a separate table for each
resistance.
Make sure not to exceed the maximum limit of
voltage for each resistance, you can calculate the
maximum voltage (use the chart).
Plot a graph for each resistance between V (xaxis) and I (y-axes).
Find the slope of each graph.
The value of the resistance R=.epols/1
Find the percentage error for each resistance.
Physics Lab
Science Collage-Imam University
Experiment 5
Continued
34

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
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Part B:
Connect the circuit as in part A; but instead of
using one resistance, use two resistors in series.
Repeat the procedure in part A to find the value
of the resistance.
Calculate the equivalent resistance of the two
resistors in series.
Find the percentage error.
Part C:
Connect the circuit as in part A; but instead of
using one resistance, use two resistors in
parallel.
Repeat the procedure in part B, but use the
resistors in parallel.
Physics Lab
Science Collage-Imam University
Experiment 5
Continued
35
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Hints and Cautions:
All electrical circuits should be handled carefully !
To protect the ammeter (or any voltage or current meter),
use the large scale first and then gradually move to a more
sensitive scale. Starting with the sensitive scale first may
seriously damage the unit .
Caution!!! Always monitor the current into the ammeter and
do not allow the current to exceed the ammeter's scale !
In this lab, use only the power supply's dc voltage outputs,
not the ac voltage outputs !
The power supply needs to be set to constant voltage mode .
You should not use the voltmeter and ammeter displays on
the power supply to record the circuit voltages and currents.
Instead, use the voltage probe from the analog multimeter .
The ammeter should always be connected in series with the
circuit elements .
The voltmeter should always be connected parallel to the
circuit elements .
Take your time and carefully plan out how you will solve
each Objective .
Physics Lab
Science Collage-Imam University
Experiment 6
Kirchhoff’s Rules
36
 Objective:
–
To investigate kirchhoff’s rules using resistors in
DC circuits connected in series and parallel.
 Theory:
When analyzing complicated DC circuits, it is
helpful to use two easily stated principles known as
Kirchhoff's rules :
Kirchhoff's Current Law :
This fundamental law results from the conservation
of charge. It applies to a junction or node in a
circuit. A point in the circuit where charge has
several possible paths to travel. In the following
figure , we see that IA is the only current flowing
into the node. However, there are three paths for
current to leave the node, and these current are
represented by IB, IC, and ID .
Physics Lab
Science Collage-Imam University
Experiment 6
Continued
37
Once charge has entered into the node, it has no
place to go except to leave (this is known as
conservation of charge). The total charge flowing
into a node must be the same as the the total charge
flowing out ,oS .edon eht fo
IB + IC + ID = IA
Bringing everything to the left side of the above
equation, we get
(IB + IC + ID) - IA = 0
∑I=0
Physics Lab
Science Collage-Imam University
Experiment 6
Continued
38

Kirchhoff's Voltage Law :
Kirchhoff's Voltage Law (or Kirchhoff's Loop Rule)
is a result of the electrostatic field being
conservative. It states that the total voltage around
a closed loop must be zero. If this were not the case,
then when we travel around a closed loop, the
voltages would be indefinite. So
∑V=0
In the following figure the total voltage around loop
1 should sum to zero, as does the total voltage in
loop eht fo stsisnoc hcihw pool eht ,eromrehtruF .2
dluohs )DCBA htap eht( tiucric eht fo trap retuo
.orez ot mus osla
Physics Lab
Science Collage-Imam University
Experiment 6
Continued
39

Resistors in series :
The current passing through the resistors in series
is equal but the voltage is devided between the
resistors.
I0=I1=I2=I3
ΔV0= Δ V1+ΔV2+ΔV3

Resistors in parallel :
The voltage passing through the resistors in parallel
is equal but the current is devided between the
resistors.
I0=I1+I2+I3
ΔV0= Δ V1=ΔV2=ΔV3
Physics Lab
Science Collage-Imam University
Experiment 6
Continued
40

Equipment :
DC power supply 4 –digital multimeters –
breadboard - resistors –connecting leads.

Procedure :
Connect the circuit with the resistors in series as
in the following figure. Measure the current and
voltage across each element and show that
kirchhoff’s voltage and current rules apply.
Physics Lab
Science Collage-Imam University
Experiment 6
Continued
41
Connect the circuit with the resistors in parallel
as in the following figure. Measure the current
and voltage across each element and show that
kirchhoff’s voltage and current rules apply.
Physics Lab
Science Collage-Imam University