# Electric Charge and Light - Physics 101 / AP Physics 1 Review with Dianna Cowern | Summary and Q&A

127.1K views
January 27, 2021
by
Physics Girl
Electric Charge and Light - Physics 101 / AP Physics 1 Review with Dianna Cowern

## TL;DR

Electromagnetic waves, such as light and radio waves, are disturbances in the electromagnetic field, which is a force field that doesn't require a medium to travel through.

## Key Insights

• 🙂 The existence of the luminiferous ether and its absence was tested by the Michelson-Morley experiment, which proved that light does not require a medium to travel through.
• 💖 Electromagnetic fields can be manipulated to create phenomena such as glowing Band-Aids and sparks through the air.
• 👮 The electromagnetic field and the force it represents can be described using mathematical formulas, such as Coulomb's law.
• 👋 Electromagnetic waves, including light, radio waves, and microwaves, are all different forms of the same fundamental force.
• 🏑 The electric field between two charged plates in a capacitor creates a constant linear field, allowing for devices like radio antennas.
• 👮 The force of electric charges interacting with each other can be calculated using Coulomb's law, while the force of gravity between masses can be calculated using the law of gravitation.
• 🙂 Light is both a wave and a particle, known as a photon.
• 🏑 The electromagnetic field is a real force field, similar to the gravitational field, and both are described using vector fields.

## Transcript

i'm gonna bring you in on a little-known secret if you open band-aids or a little bandage wrappers in the dark certain band-aids glow i am not making this up right at the bottom where the two wrappers meet as you're pulling them apart you see a thin glowing blue line and it's a really interesting little-known type of luminescence and hopefully by t... Read More

### Q: How did scientists in the 19th century attempt to determine the medium through which light travels?

Scientists in the 19th century believed in the existence of the luminiferous ether, a hypothesized medium through which light travels. They conducted the Michelson-Morley experiment in 1887 to test for the presence of the ether but found no measurable difference in the speed of light in different directions.

### Q: How is the concept of fields related to electromagnetic force?

The electromagnetic field is a force field that describes the electromagnetic force per unit charge throughout space. Just as a mass produces a gravitational field, an electric charge produces an electromagnetic vector field.

### Q: What are the two types of electric charges and how do they interact?

The two types of electric charges are positive and negative. Opposite charges attract each other, while like charges repel each other. Protons carry positive charge, and electrons carry negative charge.

### Q: What is the difference between the electric field and the gravitational field?

The electric field and the gravitational field are both vector fields, but the electric field can be positive or negative, resulting in either attractive or repulsive forces, while gravity is always attractive.

## Summary & Key Takeaways

• Certain Band-Aids glow in the dark due to a little-known type of luminescence caused by the electromagnetic force.

• X-rays, radio waves, Bluetooth frequencies, microwaves, and infrared heat are all forms of electromagnetic waves.

• Light waves do not require a medium to travel through and can travel through the vacuum of space.