Flashcards in Electric Fields Deck (20)

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1

## Define a field

### A field is a region in which a body can experience a non-contact force.

2

## What are the rules for drawing electric field lines?

###
When drawing electric fields:

The lines should never cross

The spacing of the lines represents the strength of the field

An arrow should be drawn to show the direction of force that a positive charge would feel

3

## What is a field line (electric)?

### The path a free positive test charge follows.

4

## Describe a field between two oppositely charged plates

###
Field lines run parallel

At right angles to the plates

At the edges of the field the lines are slightly curved

5

## What kind of a field is it between two oppositely charged plates?

### Uniform field

6

## Define electric field strength at a point in the field

### The force per unit charge on a positive test charge placed at that point.

7

## Electric field strength between plates is proportional to what?

###
Q/A

Q - charge

A - surface area

8

## Define electric potential at a point in an electric field

### Work done per unit positive charge on a positive test charge when it is moved from infinity to that point.

9

## Define potential gradient (electric) at a point in an electric field

### The change of potential per unit change of distance in a given direction.

10

## How is potential gradient effected if the field is non-uniform?

###
Varies according to position and direction.

Closer equipotentials means greater potential gradient at right angles to them.

11

## How is potential gradient effected if the field is uniform?

###
Equipotentials between the plates are equally spaced parallel to the plates.

Potential gradient is constant.

12

## Define electric field strength

### The negative of the potential gradient.

13

## Define Coulombs law

### The force of attraction or repulsion between two charges is proportional to the product of the masses and inversely proportional to the separation squared.

14

## What is a point charge?

### An expression for a charged object in a situation where distances under consideration are much greater than the size of the object.

15

## If two forces are in the same direction, what is the resultant electric field strength formula?

### E(1) + E(2)

16

## If two forces are in opposing direction, what is the resultant electric field strength formula?

### E(1) - E(2)

17

## If two forces are at right angles to each other, what is the resultant electric field strength formula?

###
Resolve using pythagorus.

sqrt(E(1)^2 + E(2) ^2)

18

## What can be found from a graph of force against separation?

### Area = work done = Electrical potential energy

19

## What can be found from a graph of electric field strength against separation?

### Area = Electrical potential

20