Electric field | Electric charge, electric force, and voltage | Physics | Khan Academy

TL;DR

Electric fields are the influence created by a charged object that affect other charges placed within its area, and can be calculated using Coulomb's Law.

Transcript

Let's imagine that instead of having two charges, we just have one charge by itself, sitting in a vacuum, sitting in space. So that's this charge here, and let's say its charge is Q. That's some number, whatever it is. That's it's charge. And I want to know, if I were to place another charge close to this Q, within its sphere of influence, what's g... Read More

Key Insights

• 🈂️ Electric fields are created by charged objects and influence nearby charges.
• 🈂️ Coulomb's Law can be used to calculate the force between two charged objects.
• 🏑 Electric fields become weaker as the distance from the charged object increases.
• 🏑 Electric field lines can be used to visualize the direction and strength of the field.
• 🏑 The strength of an electric field can be measured in newtons per coulomb.
• 🏑 The force exerted on a charge in an electric field can be calculated by multiplying the charge by the electric field.
• 🏑 Electric fields can be attractive or repulsive depending on the charges involved.

Questions & Answers

Q: What is an electric field?

An electric field is the influence created by a charged object that affects other charges placed within its area. It allows us to predict how the field will affect other charges.

Q: How can Coulomb's Law be used to calculate electric fields?

Coulomb's Law states that the force between two charges is proportional to the product of the charges and inversely proportional to the distance between them. By rearranging the formula, the electric field can be calculated by dividing the force by the charge.

Q: What happens to the strength of an electric field as the distance from the charged object increases?

The strength of an electric field decreases as the distance from the charged object increases. This means that the force exerted on a charge placed further away from the charge is weaker compared to a charge placed closer to it.

Q: How are electric field lines used to visualize electric fields?

Electric field lines depict the path a positive test charge would take when placed in the electric field. They show the direction and relative strength of the field. The density of field lines can also indicate the strength of the electric field.

Summary & Key Takeaways

• Electric fields are created by charged objects and influence nearby charges.

• Coulomb's Law can be used to calculate the force between two charges.

• The strength of an electric field decreases as the distance from the charged object increases.