# 6.2 Electric Fields Flashcards

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1
Q

Electric Field

A

A region in which charged bodies will experience a force

2
Q

What causes an electric field

A

A charge

3
Q

How to model a charged sphere

A

Can be modelled as a point charge when considering outside of the sphere

4
Q

How electric field lines work

A

They show the movement of a positive particle. The closer they are the stronger the field.

5
Q

Basic formula for electric field strength

A

E = Force per Charge (F/Q)

6
Q

What is the force between two charges proportional to

A

The product of their charges,

1 / distance^2

7
Q

What is the electric field strength proportional to

A

charge,

1/distance^2

8
Q

Similarities between an electric and gravitational field in terms of their strength (2)

A

Both proportional to the value of the charge/mass at a point which is causing the field
Both proportional to 1/r^2

9
Q

Difference between electric and gravitational fields

A

Gravitational fields are always attractive whereas electric fields can also be repulsive

10
Q

Fundamentally what is an electric field

A

One example of a field giving rise to a force

11
Q

Equation for electric field strength between to parallel oppositely charged plates

A

E = V/d

12
Q

What is special about a uniform electric field

A

The force/field strength is the same at any point

13
Q

Motion of a stationary particle when put in a uniform field

A

Accelerates towards one of the plates depending on its charge

14
Q

Motion of a particle moving perpendicular to a field that moves into the field

A

Will continue with same horizontal speed but will accelerate towards one of the plates. Forms a parabola.

15
Q

Permittivity

A

Measure of a materials ability to resist an electric field

16
Q

Equation for capacitor in terms of permittivity

A

εA/d

17
Q

How relative permittivity relates to actual permittivity

A

Multiply relative permittivity by the permittivity of free space (ε0) to obtain actual permittivity

18
Q

Electric Potential

A

Work done per unit positive charge to move that charge from infinity to a point in an electric field

19
Q

Electric Potential Energy of a charged object

A

The work done to move that charge from infinity to it’s current position

20
Q

Electric potential at infinity

A

zero

21
Q

How is potential difference related to electric fields

A

The electric potential at a point is the potential difference between that point and infinity
22

22
Q

What is the area under a force-distance graph between two points (with regards to electric fields)

A

The work done to move from one of the points to the other