Lab 5 – Intro to Coulomb’s Law
The Coulomb constant “k” is named after Charles-Augustin de Coulomb. This constant is associated with the electric force and is also known as the electric force constant. When charged particles interact, a force repels or attracts the particles. For instance, two like charges (such as a proton and a proton) repel each other and travel in opposite directions and two unlike charges (such as an electron and a proton) will be attracted to each other. The electrostatic force equation is shown below:
Objective: Find the Coulomb Constant.
We will use the simulation below: https://phet.colorado.edu/en/simulation/coulombs-law
Figure 1: Coulomb’s Law simulation. PHYSICS II LAB
Directions: Answer the following questions.
- What is the equation for Coulomb’s Law?
- Define each variable in the equation.
- As the distance between electric charges increase, the electric force:
- Increases b. Decreases c. Remains the same
- As the distance between electric charges decrease, the electric force:
- Increases b. Decreases c. Remains the same
- Like charges:
- Repel b. Attract c. None of these
- Unlike charges:
- Repel b. Attract c. None of these
Procedure:
- Go to the following site to access the lab simulation for Coulomb’s Law and download the simulation. https://phet.colorado.edu/en/simulation/coulombs-law
- open it
- select Macro Scale
- Set charge 1 to 10 ?? and set charge 2 to 1??. Remember 1 ?=1×106 ??
- Make sure force value box is checked.
- In data table 1 below the separation distance “r” is given to you. Separate the charges by 10 cm.
- Record the force value in data table 1. It does not matter which force value you use since you are only recording the magnitude of that force.
- Repeat the process for the rest of the values.
- Record the value for the separation distance in meters. Record your values in data table 1.
- Find 1/r2. Record your values in data table 1.
Value of ?1=________________________ ?2=________________________
r (cm) | r (m) | F (N) | 1/r2 (m-2) |
10 | |||
8 | |||
6 | |||
4 | |||
2 |
Data Analysis
- Once you have completed data table 1, make a graph of Force vs. Separation Distance. You do not need to put an equation and fit on this graph. You can use Excel or LoggerPro. Include with report.
- Make a second graph of Force vs. 1/r2.
- Use the Force vs. 1/r2 graph to find the value of the Coulomb Constant “k”. Include graph with linear fit in report.
Show work here:
4.Calculate the percentage error in k. Use the following equation to calculate the percentage error. Show your work!!!!!
% ?????=|???????????? ?????−???????? ?????| / ???????? ????? ×100%
- Watch the video “Spinning Nanofibers to Improve N-95 Masks” on electrospinning. Explain what this process is in the space provided below. How is the electric force used in this process?
Video: Spinning Nano fibers to improve N-95 masks
https://www.youtube.com/watch?v=llqx8FfnCXs
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