Point Charges in Uniform Electric Fields Lesson Plan

🔖 Topics

• Electric fields
• Electric field lines
• Motion of a point charge in an electric field

🎯 Objectives

• Describe the electric field around different charge configurations
• Determine the direction of force on a point charge in an electric field using charge conventions
• Calculate the electric force on a point charge due to an electric field
• Determine the motion of an point charge within a uniform electric field

📋 Sequence

• 🟢 Definition of electric field
• 🟢 Electric field lines
• 🟣 Electric field lines around a point charge
• 🟣 Electric field lines around a ball of charge
• 🟣 Electric field lines around a plane of charge
• 🟣 Charged particle accelerating along a uniform electric field
• 🟣 Charged particle launched in a uniform electric field, similar to a ball in a gravitational field

🖥️ Animations, Simulations, Activities

• Electric Field Hockey (Dubson et al., n.d.)

📝 Practice Problems

1. A point charge of $q=-12\mu C$ is immersed in an electric field of $\vec{E}=1000\hat{y}N/C$. What is the magnitude and direction of the force that it will feel?

2. A charge of 10 $\mu C$ is positioned at the origin while another charge of -30 $\mu C$ is positioned at the point (5 cm, 0 cm). Where around the two points (if anywhere) is the net electric force on a positive point charge equal to zero?

3. A particle with a mass of 1.1 kg and a charge of 0.5 mC starts from rest at the origin. I switch on a uniform electric field of $\vec{E}=10.7\hat{x}N/C$ at time $t=0s$. At what position will we find the particle after 5 seconds?

✅ Partial Solutions

1. 0.012 N in the $-\hat{y}$ direction
2. (-6.83 cm, 0 cm)
3. 0.060795 m

📘 Connected Resources

Dubson, M., Reid, S., Adams, W., & Harlow, D. (n.d.). Electric Field Hockey. In PhET. Retrieved January 23, 2024, from https://phet.colorado.edu/en/simulations/electric-hockey