6.2 Electric Fields

Question 1

Define an electric field?

Answer 1

-Electric field: the region around a body in which charged bodies will feel a force due to the electric charge of the body

Question 2

Define electric field strength

Answer 2

-It is the force per unit positive charge, units are newtons per coloumb and it is the force that a charge of +1C would experience if placed in the field

Question 3

What is the equation for electric field strength?

Answer 3

E=F/Q
E:electric field strength
F: size of force in Newtons
Q: size of positive charge

Question 4

How is the strength of the electric field shown and what does the direction of the electric field lines tell us?

Answer 4

-The closer the electric field lines the stronger the electric field
-The direction of the lines tells us the direction a positive charge would move if placed at that point

Question 5

State coloumbs law?

Answer 5

-Coloumbs law states that electrical force between two charges is directly proportional to the product of their charges and inversely proportional to the square of their seperation/distance

Question 6

What is the value for the permittivity of free space (Ε₀)/ absolute permittivity of air?

Answer 6

8.85*10^-12 (C^2m^-2N^-1)

Question 7

What is the relationship between electric field strength and distance from point charge?

Answer 7

-They are inversely proportional

Question 8

What is permittivity and relative permittivity?

Answer 8

Permittivity: a constant related to size of the capacitance
Relative permittivity: the ratio of the absolute permittivity of the insulating material and the absolute permittivity of air

Question 9

What is an equation for electric field strength between two charged parralel plates?

Answer 9

E=V/D
E:electric field strength
V: potential difference between plates
D:seperation

Question 10

What will happen if you place a positive and negative charged particle in a uniform electric field?

Answer 10

-The positive particle will accelerate towards the negative plate and the negative particle will accelerate towards the negative plate

Question 11

What is the electric potential and electric potential energy?

Answer 11

-Electric potential: work done per unit of charge to move that charge from infinity (where potential is zero) to any point in an electric field
-Electric potential energy: is the work done to move that charge from infinity to a point in the electric field

Question 12

What is the area under a force-distance graph equal to?

Answer 12

Work done