Imam Mohammed bin Saud University Science Collage General Physics Lab Manual Physics Lab Science Collage-Imam University Science Collage-Imam University

Physics 101 Lab General physics course is mainly about mechanics and electricity. You will perform basic physics experiments. Hope you enjoy your physics lab …. Physics Lab Science Collage-Imam University Science Collage-Imam University

Lab Rules 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 Science Collage-Imam University

Lab report guide Your lab report should consist of: 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: Here you present your data, explain how you reduced your data to a value for the OBJECTIVE, and reflect on the reliability of your result. Data summary: Present the collected raw data here, in tabular form. Any graphs you created should be included in this section, also. Graphs should be drawn on special graphing paper with appropriate scaling. Graphs, tables and figures must have legible titles and captions. Physics Lab Science Collage-Imam University Science Collage-Imam University

Lab report guide Analysis: Describe, in one paragraph, the mathematical steps used to convert the raw data into the final value reported for the objective. Errors: In a single paragraph comment on the accuracy and precision of the apparatus and include a discussion of the experimental errors and an estimate of the error in your final result. 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: Restate your results, including the uncertainty in any numerical results. Compare your result with the accepted value. Appendices: Include here the answers to questions assigned from the lab manual. They should be answered in complete sentences using appropriate scientific terminology. Physics Lab Science Collage-Imam University Science Collage-Imam University

Experiment 1 Balancing force (force table) 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. Physics Lab Science Collage-Imam University Science Collage-Imam University

Experiment 1 Continued 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. Where FR is the resultant force and FE is the equilibrant force. Physics Lab Science Collage-Imam University Science Collage-Imam University

Experiment 1 Continued 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. 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. F2 F1 FR Physics Lab Science Collage-Imam University Science Collage-Imam University

Experiment 1 Continued 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 Science Collage-Imam University

Experiment 1 Continued Equipment: Force table – stand base – pulleys – hangers – weights (slotted masses) – strings – center ring – protractor . Physics Lab Science Collage-Imam University Science Collage-Imam University

Experiment 1 Continued 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 Science Collage-Imam University

Experiment 1 Continued 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 Science Collage-Imam University

Experiment 1 Continued 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 Science Collage-Imam University

Experiment 1 Continued Data: Percentage Error: Percentage error Balancing force Force 2 Force 1 experimentally graphically Magnitude Angle Physics Lab Science Collage-Imam University Science Collage-Imam University

Experiment 2 Acceleration of Linear uniform motion 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. where: Displacement or change in position d: Original velocity, the velocity at the start of the acceleration vo: Final velocity, the velocity at the end of the acceleration. vf: Acceleration, this is a constant acceleration a: Time, this is the time period of the acceleration. t: Physics Lab Science Collage-Imam University Science Collage-Imam University

Experiment 2 Continued Equipment: Track – trolley – holding magnet – electronic stop clock – light barrier – pulley – mass hanger – slotted weights – cables. Physics Lab Science Collage-Imam University Science Collage-Imam University

Experiment 2 Continued 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 Science Collage-Imam University

Experiment 2 Continued 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. Time square s2 Average Time s Time 3 Time 2 Time 1 Distance m Physics Lab Science Collage-Imam University Science Collage-Imam University

Experiment 2 Continued 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. Physics Lab Science Collage-Imam University Science Collage-Imam University

Experiment 3 Free fall 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: where: Vertical displacement Δy: Original velocity, the velocity at the start of the acceleration vo: Final velocity, the velocity at the end of the acceleration. vf: Acceleration due to gravity g: Time, this is the time period of the acceleration. t: Physics Lab Science Collage-Imam University Science Collage-Imam University

Experiment 3 Continued 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 Science Collage-Imam University

Experiment 3 Continued 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. Time square s2 Average Time s Time 3 Time 2 Time 1 Height m Physics Lab Science Collage-Imam University Science Collage-Imam University

Experiment 3 Continued 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. 9- Repeat the previous steps using a different mass ball. 10- State your observation Physics Lab Science Collage-Imam University Science Collage-Imam University

Experiment 4 Conservation of mechanical energy 24 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 24 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 Science Collage-Imam University

Experiment 4 Continued 26 (1/2) m vi2 + m g hi = (1/2) m vf2 + m g hf If the object starts from rest, we get: m g hi = (1/2) m vf2 + m g hf (1/2) m vf2 = m g hi – m g hf (1/2) vf2 = g hi – g hf From the equations of motion: d = (1/2) (vi + vf) t 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 Science Collage-Imam University

Experiment 4 Continued Equipment: 27 Equipment: Track – trolley – holding magnet – electronic stop clock – light barrier – cables. Physics Lab Science Collage-Imam University Science Collage-Imam University

Experiment 4 Continued Procedure: 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 Science Collage-Imam University

Experiment 5 Ohm’s Law Objective: 29 Objective: 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 29 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 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=R1+R2 The equivalent resistance, R, for the resistors in parallel is given by 1/R = (1/R1)+(1/R2) R1 R2 R1 R2 Physics Lab Science Collage-Imam University 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 analogو multimeters could be used. Physics Lab Science Collage-Imam University Science Collage-Imam University

Experiment 5 Continued Procedure: Part A: 33 Procedure: 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 (x-axis) and I (y-axes). Find the slope of each graph. The value of the resistance R=1/slope. Find the percentage error for each resistance. Physics Lab Science Collage-Imam University 33 Science Collage-Imam University

Experiment 5 Continued Part B: 34 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 Science Collage-Imam University

Experiment 5 Continued Hints and Cautions: 35 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 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 36 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 of the node. So, 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 Science Collage-Imam University

Experiment 6 Continued Kirchhoff's Voltage Law: 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 loop2. Furthermore, the loop which consists of the outer part of the circuit (the path ABCD) should also sum to zero. Physics Lab Science Collage-Imam University Science Collage-Imam University

Experiment 6 Continued Resistors in series: 39 Resistors in series: The current passing through the resistors in series is equal but the voltage is devided between the resistors. 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 I0=I1+I2+I3 ΔV0= Δ V1=ΔV2=ΔV3 Physics Lab Science Collage-Imam University Science Collage-Imam University

Experiment 6 Continued Equipment: Procedure: 40 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 Science Collage-Imam University

Experiment 6 Continued 41 Physics Lab Science Collage-Imam University 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 Science Collage-Imam University