# Electric Fields Flashcards

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1
Q

What creates an electric field?

A

An electric charge.

2
Q

Define electric field strength.

A

Force per unit positive charge.

3
Q

What is the symbol for electric charge and what is it measured in?

A

Q, measured in coulombs (C).

4
Q

How do electric field lines represent an electric field?

A

The arrows on the lines represent the direction of the field and how close the lines are represent how dense the field is at that point.

5
Q

When do we use Coulomb’s law?

A

To find the force of attraction or repulsion between to point charges.

6
Q

What does epsilon represent?

A

Permittivity of a material

7
Q

What is the permittivity of free space?

A

Epsilon 0.

8
Q

What is the letter used to represent electric field strength?

A

E.

9
Q

What do we use the equation E=V/d to find?

A

The uniform field strength between two electrically charged parallel plates

10
Q

How does a uniform electric field affect charged particles passing through it?

A

The particle will move according to circular motion, in the same direction as the field lines if positively charged, and in the opposite direction if negatively charged.

11
Q

List three similarities between electric and gravitational fields.

A

1) g is force per unit mass, and E is force per unit positive charge.
2) Newton’s law of gravitation and Coulom’s law are both inverse square laws.
3) Point masses and point charges create radial fields.

12
Q

List three differences between electric and gravitational fields.

A

1) Gravitation fields can only be attractive, electric fields can be attractive or repulsive.
2) Objects can be shielded from electric fields, but not gravitational.
3) The medium between the points affects electric forces, but not gravitational forces.

13
Q

Describe an experiment that provides evidence for an electric field.

A

Attach a small piece of gold foil to the end of an insulator. When you hold the foil between two charged plates, the gold foil should bend towards the negatively charged plate. This shows there is an electric field present.