# Physics

**Electric field and electric potential ****– **Lab Report Check List

Part I a. Electric field of the point charge distributions

· Arrange four sensors around the charge at the same distance (two on vertical and two horizontal axes).

· Compare the values (the lengths) of the electric field vectors from the screen.

· Explain your observations qualitatively.

· Calculate the electric field using equation (3) for your configuration.

· Compute the average value from all sensors’ readings and compare with the calculated value.

· Use screen capture (print screen: Ctl + PrtScn), paste the captures in word file, label and attach to your lab report

· Explain your observations qualitatively and quantitatively when you are adding charges.

· Compare your readings for the *E*-field at the points 0.5 m and 1.0 m from the source charge and compare it with the sensors readings.

· Check the *Principle of Superposition *according to the manual. Explain.

Part I b. Electric potentials and equipotential lines of point charge

· Measure and record the values of the potentials at 1; 2; 3; 4; 5 major grid distances (0.5 m; 1.0 m; 1.5 m; 2.0 m; 2,5 m) from the charge in two directions of radii (horizontal and vertical).

· Make two graphs: potential *V _{ave}* vs. distance

*r*and

*V*vs. inverse of distance, 1/

_{ave}*r*using software Logger Pro.

· Repeat the experiment with negative charge answer the questions from the manual.

Part I c. Electric field, potential and equipotential lines of electric dipole

· Generate five equipotential lines with the magnitude: 1.5V, 3.0V, 4.5V, 7.0V and 10.0V around each charge of the electrical dipole.

· Answer the questions from the manual.

Part II a. Electric field and electric potential between parallel plates

· Charge the pith balls with maximum charge and drag the single pith ball pendulum and release it over the identical attachment hook above the parallel plates.

· Adjust the voltage on power supply to the maximum value (extreme position).

· Measure the deflection angle *θ* of the pith ball using the protractor.

· Draw a free body diagram of the ball.

· Apply Newton’s second law for charged pith ball in equilibrium position.

· Using the value of the charge on the pith ball calculate the maximum value *E _{max}* of the electric field between parallel plates.

· Measure the separation distance *d * between the parallel plates using ruler.

· Calculate the *V _{max }* between the plates

· Adjust the deflection angle to *θ *= 8° and calculate the values of the force – *F _{1},*electric field –

*E*and corresponding voltage –

_{1}*V*

_{1}.* *

Part II b. Charging rod with charge # = 100

· Repeat the experiment using the charging rod with charge # =100.

· Measure the deflection angle *θ* of the pith ball using the protractor.

· calculate the maximum voltage of power supply from equilibrium condition.

· Compare it with value you found in the previous part.

· Calculate the force*,*electric field and corresponding voltage when the pith ball’s deflection angle *θ *= 8°.

· Calculate the ratio V_{2}/V_{1} and compare with the expected value.

**Electric field and electric potential ****– **Lab Report Check List

Part I a. Electric field of the point charge distributions

· Arrange four sensors around the charge at the same distance (two on vertical and two horizontal axes).

· Compare the values (the lengths) of the electric field vectors from the screen.

· Explain your observations qualitatively.

· Calculate the electric field using equation (3) for your configuration.

· Compute the average value from all sensors’ readings and compare with the calculated value.

· Use screen capture (print screen: Ctl + PrtScn), paste the captures in word file, label and attach to your lab report

· Explain your observations qualitatively and quantitatively when you are adding charges.

· Compare your readings for the *E*-field at the points 0.5 m and 1.0 m from the source charge and compare it with the sensors readings.

· Check the *Principle of Superposition *according to the manual. Explain.

Part I b. Electric potentials and equipotential lines of point charge

· Measure and record the values of the potentials at 1; 2; 3; 4; 5 major grid distances (0.5 m; 1.0 m; 1.5 m; 2.0 m; 2,5 m) from the charge in two directions of radii (horizontal and vertical).

· Make two graphs: potential *V _{ave}* vs. distance

*r*and

*V*vs. inverse of distance, 1/

_{ave}*r*using software Logger Pro.

· Repeat the experiment with negative charge answer the questions from the manual.

Part I c. Electric field, potential and equipotential lines of electric dipole

· Generate five equipotential lines with the magnitude: 1.5V, 3.0V, 4.5V, 7.0V and 10.0V around each charge of the electrical dipole.

· Answer the questions from the manual.

Part II a. Electric field and electric potential between parallel plates

· Charge the pith balls with maximum charge and drag the single pith ball pendulum and release it over the identical attachment hook above the parallel plates.

· Adjust the voltage on power supply to the maximum value (extreme position).

· Measure the deflection angle *θ* of the pith ball using the protractor.

· Draw a free body diagram of the ball.

· Apply Newton’s second law for charged pith ball in equilibrium position.

· Using the value of the charge on the pith ball calculate the maximum value *E _{max}* of the electric field between parallel plates.

· Measure the separation distance *d * between the parallel plates using ruler.

· Calculate the *V _{max }* between the plates

· Adjust the deflection angle to *θ *= 8° and calculate the values of the force – *F _{1},*electric field –

*E*and corresponding voltage –

_{1}*V*

_{1}.* *

Part II b. Charging rod with charge # = 100

· Repeat the experiment using the charging rod with charge # =100.

· Measure the deflection angle *θ* of the pith ball using the protractor.

· calculate the maximum voltage of power supply from equilibrium condition.

· Compare it with value you found in the previous part.

· Calculate the force*,*electric field and corresponding voltage when the pith ball’s deflection angle *θ *= 8°.

· Calculate the ratio V_{2}/V_{1} and compare with the expected value.

The formal Lab Report is written from the third person; in the passive form, in the past tense. It includes the following parts:

Expression of the experimental results is an integral part of science. The lab report should have the following format:

· Cover page – course name , title of the experiment, your name (prominent), section number, TA’s name, date of experiment, an *abstract*. An abstract (two paragraphs long) is the place where you briefly summarize the experiment and cite your main experimental results along with any associated errors and units. *Write the abstract after all the other sections are completed*.

The main body of the report will contain the following sections, each of which must be clearly labeled:

· Objectives – in one or two sentences describe the purpose of the lab. What physical quantities are you measuring? What physical principles/laws are you investigating?

· Procedure – this section should contain a brief description of the main steps and the significant details of the experiment.

· Experimental data – your data should be tabulated neatly in this section. Your tables should have clear headings and contain units. All the clearly labeled plots (Figure 1, etc.) produced during lab must be attached to the report. The scales on the figures should be chosen appropriately so that the data to be presented will cover most part of the graph paper.

· Results – you are required to show sample calculation of the quantities you are looking for including formulas and all derived equations used in your calculations. Provide all intermediate quantities. Show the calculation of the uncertainties using the rules of the error propagation. You may choose to type these calculations, but neatly hand write will be acceptable. Please label this page Sample Calculations and box your results. Your data sheets that contain measurements generated during the lab are not the results of the lab.

· Discussion and analysis – here you analyze the data, briefly summarize the basic idea of the experiment, and describe the measurements you made. State the key results with uncertainties and units. Interpret your graphs and discuss what trends were observed, what was the relationship of the variables in your experiment. An important part of any experimental result is a quantification of error in the result. Describe what you learned from your results. *The answers to any questions posed to you in the lab packet should be answered here.*

· Conclusion – Did you meet the stated objective of the lab? You will need to supply reasoning in your answers to these questions.

*.*

All data sheets and computer printouts generated during the lab have to be labeled Fig.1, Fig. 2, and included at the end of the lab report.

**Important Note**

· All data sheets and computer printouts generated during the lab have to be labeled Fig.1, Fig. 2, and included at the end of the lab report.

· The Post-Lab Checklist does not need to be attached when the lab report is submitted.