←   (ne09) Drawing Q, E & V   →

Components

Part 1 Fields and Potential	Part 2 Hand-Draw Line Charges	Part 3 Hand-Draw Components
電池電壓	手繪線費	手繪零件

Guided Learning (YouTube)

In this series of videos (making use of the HTML5 PHeT simulation "charges-and-fields" linked to above), you will guided in the drawing of charge (Q), Electric field lines and equipotential surfaces (V=constant) for a variety of charge distributions starting with single isolated charges, and then dipoles, ion traps, lines of charges and finally antennas.

Video Links

1. Introduction, Single Charges, Preparing to Solve for Dipoles
2. Dipoles to Line of Charge
3. Lines of Charges to Batteries and Antennas
4. Antennas -- Q, V, E and Light!

Worksheet

1. Download the Worksheet.
2. Using the simulation as an aid and the vidoes as a guide, complete electric field (E) and equi-potential (V=const) lines for each of the pictures.
3. Hand in at the begining of next class if you cannot finish in class.

Key Concepts

Electric field (E) Lines

1. Start at a positive (+) charge
2. End at a negative (−) charge
3. Separation between lines reflects the strength of the field.
   (closer together → stronger field)
4. Electric Field (E) lines must have arrows to show direction

Equi-Potential Surfaces (3D), Lines (2D) (V=constant)

1. No direction
2. Perpendicular (⟂) to E
3. Potential at infinity set to zero (V(∞)=0).
4. closer together → more rapid ΔV, higher E

Steps in Using Simulation

1. Place charges on the screen.
2. Observe the E-field vectors
3. Use the tool to draw equi-potential lines with constant ΔV separation
4. Write the value of the potential (V=??) on each line
5. Add sensors (i.e., + test charges) to show the electric field vectors.
6. Draw the electric field

Practice (Use PhET Simulation as Aid)

1.Basic Single Charges

1. single positive (+)
2. single negative (−)
3. dipole (+ & −)
4. two positive (+)
5. triangle of positive (+)
6. square of positive (+) charges (+ ion trap)

2. Lines of Charges

1. line of negative (−) charge
2. line of charge + single negative (−) charge
3. line of charge + single positive (+) charge

3. Batteries, Antennas, Capacitors

1. battery
2. battery with wire
3. battery with antenna, broken circuit
4. battery with antenna,complete circuit