phys lab report

 

This criterion is linked to a Learning OutcomeSection I – Report Format (5%)You can use Owl Purdue website for help with format
•

https://owl.purdue.edu/owl/research_and_citation/apa_style/apa_style_introduction.htmlLinksLinks to an external site.

to an external site.
• Title Page with Experiment Title, physics course no/section, report date & your name
• Format – use APA guidelines See OWL PURDUE website
• All equations and calculations must use an equation editor
• If using references points will be used from this section.

5 ptsFull Marks

0 ptsNo Marks

5 pts

This criterion is linked to a Learning OutcomeSection II – Abstract (10%)Focus on the experimental objectives and verify them.
• In paragraph form, state the experiment objective(s) and how it was tested.
• Include a brief description of the experiment
• State the results and error results. Are the error % high or low and why important?
• Why is this experiment important and what are possible applications of this experiment

10 ptsFull Marks

0 ptsNo Marks

10 pts

This criterion is linked to a Learning OutcomeSection III – Introduction (15%)• Breakdown of these 15 points:
7 points derivations, 3 points units and variables defined, 2 points for figures used and 3 points for use of Physics history (how did Physics get to this experiment)
1st lab report use text from lecture, appropriate chapters that follow the experiment
2nd lab report: use text from lecture, appropriate chapters that follow the experiment
• Write a brief paragraph stating significance and objectives of the experiment.
• Narrative should prove your understanding of the physics of the experiment.
• Include explanation/derivation of equations used. All symbols must be defined.

15 ptsFull Marks

0 ptsNo Marks

15 pts

This criterion is linked to a Learning OutcomeSection IV – Apparatus (5%)• You may include drawings of the apparatus, if possible/applicable, and a listing of equipment if necessary. Only summarize the equipment used, what is connected to what, and for what purpose.
• When appropriate, trace the signal path completely
• Do not state numerical results in this section.

5 ptsFull Marks
0 ptsNo Marks
5 pts

This criterion is linked to a Learning OutcomeSection V – Experimental Procedure (5%)• Write a brief narrative of the procedures followed to obtain data (summary of procedure). This may be 1-2 paragraphs in length. How did you get the data from the experiment?
• Include which buttons you utilized during the experiment
• Do not copy all the detailed procedures from the manual.
• Include any problems you may have had and how you overcame them.
• Write in complete sentences and as if you are telling the reader about the process you used.

5 ptsFull Marks
0 ptsNo Marks
5 pts

This criterion is linked to a Learning OutcomeSection VI – Data (15%)• You should include original data sheets initialed by instructor at completion of experiment.
• You must transfer the data to an excel sheet for easier analysis.
• Example: (Tables should be professional looking follow APA format).

 Example(Refer to your syllabus Lab report section)

15 ptsFull Marks
0 ptsNo Marks
15 pts

This criterion is linked to a Learning OutcomeSection VII – Calculations and Graphs (20%)1st report the calculations are critical in this area. Show all calculations
• You should show each type of calculation with appropriate tables, graphs, numerical results and errors.
• All tables/graphs must be referenced and labeled properly.
• All symbols must be defined. Units must be included.
• Discuss the graph and the results that the graph represents in terms of your overall goal of a physical constant.
 Example:(Refer to your syllabus)

20 ptsFull Marks

0 ptsNo Marks

20 pts

This criterion is linked to a Learning OutcomeSection VIII – Discussion of Results and Error Analysis (20%)2nd report is critical in the discussion area.Analyze why some graphs are symmetrical, why some are “jagged”
Summarize any unusual problem or concerns with the experiment, including statements of how the experiment could be improved.
When discussing error, make sure to draw from the following calculations to give quantitative results: * actual percent error and total expected error (show calculation)
Use questions from your lab manual for a better analysis and to support your discussion of the results. Incorporate the lab manual questions within the flow of your discussion section.

20 ptsFull Marks
0 ptsNo Marks
20 pts

This criterion is linked to a Learning OutcomeSection IX—Conclusion (5%)• Include the physics of the experiment in the conclusion
• Complete discussion of how the results of the experiment support the theory.
• How can errors be reduced?
• Is the method sufficiently precise and accurate?

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UNT PHYS 2240 Lab ENG_PHYS_2 E&M_FALL_2020 – Alymjan
Rejepov/Experiment 4: Series and Parallel Circuits/Experiment

Assignment # 4B
Name Lab 4 Experiment
I worked in a group with

Evan Hathaway – Jun 30, 2020, 11:22 AM CDT

Update and Submit

Equipment

Content LA Thirteen – Jun 11, 2020, 11:06 PM CDT

1 AC/DC Electronics Laboratory EM-8656

1 Set of circuit components

1 Digital Storage Oscilloscope TBS-1052

2 Oscilloscope Probes

1 Digital Multimeter EX 330

1 DC Power Supply TP3005T

Content LA Thirteen – Jun 11, 2020, 11:06 PM CDT

Resistor Check

Content LA Thirteen – Jun 11, 2020, 11:06 PM CDT

To properly analyze circuits and series and parallel, we should know the actual resistance values of each resistor being used. In other words, recall that
each resistor’s resistance value can fall within an acceptable tolerance range, denoted by the usually gold (+/- 5%) or silver (+/- 10%) band. We should
then first measure each resistor with our digital multimeter.

1. Locate the six resistors needed: 2x 100 Ω, 2x 330 Ω, and 2x 560 Ω resistors.

2. Begin by using the DMM to measure each resistor. Make sure the meter is set to measure resistance, and record each resistance value
in Table 1 below.

Table 1: Measured Resistor Values

R1 = 330 Ω R2 = 560 Ω R3 = 100 Ω R4 = 100 Ω R5 = 560 Ω R6 = 330 Ω

Content LA Thirteen – Jun 11, 2020, 11:09 PM CDT

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Procedure A: Series and Parallel Resistor Circuits

Content LA Thirteen – Jun 11, 2020, 11:10 PM CDT

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Figure 4: The digital multimeter is inserted in series with the power supply to determine the current provided by the source. The “A” symbol refers to
ammeter, which is the DMM in current sensing mode. Note: it does not matter with which terminal (+ or -) the DMM is placed in series, since the
current entering the circuit must equal the current leaving the circuit. This will be the concept of Lab 6 (Kirchhoff’s Laws).

In this experiment, we must measure the total current being provided to each circuit, which is directly being supplied by the DC Power supply.
Therefore, we will use the digital multimeter in current sensing mode, i.e., as an ammeter, to measure the current before it arrives to the circuit, as
shown in Figure 4.

1. Construct the first circuit shown in Circuit Diagram 1 (Fig 3).

2. As shown in Figure 4, insert the digital multimeter in series with the DC power supply. Doing this will directly (and accurately) measure the
current provided to the entire circuit by the power supply.

Use banana plugs for this connection, rather than the normal DMM probes.

3. Set the DMM to be on the milliampere scale by turning the dial to “mA.”

4. DO NOT connect the power supply to the circuit yet.

5. Turn on the DC power supply. Verify both voltage and current are set to zero by doing the following

a. Press the Voltage knob and set to 0.000 Volts.

b. Press the Current knob and set to 0.000 Amps.

6. Connect the power supply / DMM combo to your circuit.

7. Set Voltage on the DC power supply to 15.00 V

8. SLOWLY increase the current in increments of 0.010 A until 15.00 V has been reached on the power supply. For the first circuit, only about
0.020 A or 0.030 A should be needed. Once the current has been adjusted, you will notice it decreases slightly, such that 15.00 V is sustained.

9. After the reading stabilizes, record the current being measured by the DMM in Table 2 below.

10. Set the current to 0.000 A on the DC power supply.

11. TURN OFF the DC power supply.

12. Calculate the theoretical equivalent resistance Req for the circuit by using equations 2 and 3. Enter this value in Table 2. Use the measured

values of each resistor for this step.

13. Compute the measured equivalent resistance Req by applying Ohm’s law: where

V = 15 Volts and I is equal to the measured current found previously in step 9. Enter this value in Table 2.

14. Compare the theoretical and measured equivalent resistances by calculating the percent difference between the two, and enter the result in
Table 2.

15. Disassemble circuit 1, construct circuit 2, turn on the DC power supply, and repeat steps 8-14 for circuit 2.

16. Repeat step 15 for circuits 3 and 4.

17. Set the current and voltage on the DC power supply both to 0.000 V and 0.000 A.

Table 2: Resistance Values

Content LA Thirteen – Jun 11, 2020, 11:28 PM CDT

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Circuit Diagram
Theoretical Req

(Ω)

Measured

Current (mA)
Measured Req (Ω)

Percent
Difference

1

2

3

4

Procedure B: Series and Parallel Lightbulb Circuits

Content LA Thirteen – Jun 11, 2020, 11:29 PM CDT

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Just as in the previous section, here you will measure each lightbulb’s resistance individually, then use them to construct series/parallel combinations
and measure the equivalent resistance of these combinations. As you previously discovered in the Ohm’s Law lab, the resistance of the lightbulbs is
not constant.

In this experiment, we will not need an ammeter to measure the current provided by the power supply. The reason for this is that the current being
drawn by the lightbulbs is much larger than with the resistors. In general, the resistance of the bulbs is much less than the resistors used in the previous
section. Hence, we will read the current and voltage directly off the power supply.

1. Connect lightbulb A in series directly to the power supply, as shown in Figure 5.

2. Turn on the DC power supply. The current and voltage should be zero from the previous experiment. Set the voltage to 2.00 V

3. SLOWLY increase the current in increments of 0.010 A (10 mA) to reach the 2.00 V. This should be about 0.260 A for the specific
lightbulbs being used.

4. Calculate the resistance of bulb A with these parameters, using , using the voltage and current as displayed by the power supply.
Record the value in Table 3 below.

5. Decrease the current to zero.

6. Repeat steps 3-5 for lightbulbs B and C.

7. Make sure the current is set to zero. Place bulbs A & B in series as shown in Figure 6.

8. Repeat steps 3-5.

9. Make sure the current is set to zero. Place bulbs A & B in parallel as shown in Figure 7

10. Repeat steps 3-5.

11. Make sure the current is set to zero. Place bulb A in series with bulbs B & C which are in parallel as shown in Figure 8.

12. Repeat steps 3-5.

Table 3. Lightbulb circuit resistance values

Bulb System
Measured Resistance

(Ω)

A

B

C

A&B Series

A&B Parallel

Series Parallel

Content LA Thirteen – Jun 11, 2020, 11:40 PM CDT

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Conclusions

Content LA Thirteen – Jun 11, 2020, 11:41 PM CDT

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Series and Parallel Circuits

1. How well did the theoretical values compare to the experimental values?

2. What are sources of error in this experiment, and how could they be minimized?

Light Bulb

3. How does the brightness of two bulbs in series compare to a single bulb? Explain this in terms of power.

4. How does the brightness of two bulbs in parallel compare to a single bulb? Explain your answer.

5. Explain what is happening in the series parallel setup.

Content LA Thirteen – Jun 11, 2020, 11:43 PM CDT

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UNT PHYS 2240 Lab ENG_PHYS_2 E&M_FALL_2020 – Alymjan
Rejepov/Experiment 4: Series and Parallel Circuits/Background
Information

Introduction

Content LA Thirteen – Jun 10, 2020, 11:28 PM CDT

The purpose of this experiment is to help the student understand series and parallel circuits, how to calculate their equivalent resistance, and how to
construct them in the laboratory. The resistance of four circuits will be determined both theoretically and experimentally. The experimental resistance
will be calculated by measuring both the voltage and current of the constructed circuits. The behavior of light bulbs connected in series and parallel
will also be examined.

Content LA Thirteen – Jun 10, 2020, 11:28 PM CDT

Theory

Content LA Thirteen – Jun 10, 2020, 11:28 PM CDT

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Calculating Equivalent Resistance

A resistor generally means a device that obeys Ohm’s Law (many devices do not) and has a resistance R.

Ohm’s Law: V = IR Equation 1

Two (or more) resistors can be connected in series (as in circuit diagram 1), or in parallel (as in circuit diagram 2). Resistors can also be connected in a
series/parallel circuit as shown in circuit diagrams 3 & 4. An equivalent resistor is a single resistor that could replace a more complex circuit and
produce the same total current when the same total voltage is applied. This is shown in Figures 1 and 2. For a series circuit, the resistances are
additive:

Req = R1 + R2 Equation 2

where Req is the equivalent resistance.

Figure 1: Resistors in Series

For a parallel circuit, the resistances add as reciprocals

Remember, when adding fractions, they must have like denominators!

We must multiply each fraction so that they have common denominators.

So we get that

If we take the reciprocal of both sides we obtain another expression for calculating equivalent resistance in parallel circuits.

Content LA Thirteen – Jun 11, 2020, 11:05 PM CDT

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A more complex circuit like Circuit Diagram 3 can be handled by combining R1 and R2 into an equivalent resistance with Equation 4. That equivalent

resistance is then put in series with R3 and equation 2 is used to find the equivalent resistance for the whole circuit. Circuit Diagram 4 can be handled

in a similar manner.

In series circuits the current is the same through each resistor, but the voltage drop across each resistor may be different. Likewise, in a parallel circuit
the voltage drop across each resistor is the same, but the current through each resistor may be different.

Power

A simple understanding of power will help the student understand what is physically happening in this experiment. Power is the rate at which work is
done for a system. Electrical power is defined as:

P = IV Equation 5

Where P is the power measured in watts, I is the current in amperes, and V is the voltage drop across the device measured in volts. It is useful to
consider power in terms of current and resistance. Remember that Ohm’s law relates voltage to current and resistance. If this is plugged into equation
4, another way of writing power is developed. This is only true for devices that obey Ohm’s law!

P = IV =I(IR) = I2R Equation 6

R is the resistance measured in ohms. Power is directly proportional to resistance and the current squared. If two devices have the same resistance, but
device 1 has twice as much current running through it compared to device 2, device 1 will have 4 times the power.