Charge Lab

Please do based on the instructions from the video, the one below is just for support:
http://thephysicsaviary.com/Physics/Programs/Labs/SpaceAroundChargeLab/

The sensor is initially set to only record the electric potential (voltage). Click on the sensor (once should do it) so that it displays both the magnitude of the electric field and the voltage. The arrow attached to the sensor tells you the direction of the local electric field. When you record your data, you will need to note whether it is in the radial direction (away from the central charge) or the negative radial direction (toward the central charge). Keep in mind that the E value given by the sensor is only the magnitude of the electric field.

Use the Sensor Position controls to reposition the charge. The straight arrows move the particle in the direction indicated. The circular arrows allow you to move the sensor clockwise or counterclockwise about the central particle.

The goal of your lab report is to communicate to the readers enough information so that they could do the lab, even if they have not seen it before.

Introduction

Give one or two sentences only, stating that you are testing the formulas for the electric field and electric potential around a point charge, using a digitally simulated point charge and sensor. (Use you own words here.)

The Apparatus section will always include a screenshot of the lab, with all the relevant parts labelled with their names. Anything that you manipulate or read in the lab is relevant. If it is mentioned in the Procedure, then it better be labelled here.

When you write up your Procedure section of the lab report, break up the procedure into a series of numbered steps. Make an individual step for recording each variable. You should also have a step that tells the reader to, “Repeat the above steps 5 more times.” Do not discuss the calculations in this section.

Your Raw Data table should have the following column headings: q, the charge that is creating the local electric field, r, the distance from the center of the central charge, Eexp the electric field vector at the sensor distance, r, (an example would be -5613 N/C r, where r stands for “r hat”, an r with a hat on top to indicate that it is the radial unit vector. The minus sign means that the electric field is pointing in the negative radial direction, or toward the central charge.) and Vexp, the electric potential at the sensor location, r. I also include an initial column for the number of each data run.

In this lab, you will do a total of 6 data runs. Make sure to vary the central charge, its sign, and the location of the sensor as you do the different data runs.

Calculations

After you collect your data, you will compare your experimentally measured Eexp (magnitude now) and Vexp with the theoretical values calculated with the following formulas:

EthLaTeX: \:=\frac{k_cq}{r^2}= k c q r 2 r, where kc is Coulomb’s constant, q is the central charge, and r is the distance from the central charge to the sensor. The unit vector, r, indicates the radial direction (away from the central charge). You may use the bold r instead of “r hat” in your lab reports if you prefer.

LaTeX: V_{th}=\frac{k_cq}{r}V t h = k c q r, where the variables are defined exactly the same was as in the electric field equation.

Find the percentage error in each case:

LaTeX: \%\:error\:in\:E\:=\:\frac{\left|E_{th}-E_{exp}\right|}{E_{th}}\times100\%% e r r o r i n E = | E t h − E e x p | E t h × 100 % , where we are now using the magnitudes of the electric fields.

LaTeX: \%\:error\:in\:V\:=\frac{\left|V_{th}-V_{exp}\right|}{\left|V_{th}\right|}\times100\%% e r r o r i n V = | V t h − V e x p | | V t h | × 100 %

Present the results of your calculations for all data runs in a table with the headings:

Eth, Eexp, % error in E, Vth, Vexp, % error in V. Note that you are only stating the magnitudes of the electric fields in this table. Make sure that you explain what each of these headings represents (as I have done above).

In the Conclusions section, state how well your experimental data conformed to the theoretical values. You should always say that it agreed within (the largest) percent error.

Use the standard lab report format. Make sure to watch the recorded lecture (which will be in the Modules, right next to the Module for the link to this lab).