electric fields definitions

Question 1

Electric Field

Answer 1

A region within which a charged object will experience a non-contact electrostatic force.

Question 2

Electric Field Strength

Answer 2

defined as the electric force per unit charge.

E= F/Q

Question 3

Electric Field Strength in terms of a charged point mass

Answer 3

The electric field strength, E, due to a point charge Q is given by: E= kQ/r^2

k being 1/4pie0

Question 4

Define permittivity of free space

Answer 4

The permittivity of free space is a physical constant that reflects the ability of electrical fields to pass through a classical vacuum.
Charge may be considered to be at the centre

Question 5

Coulomb’s Law

Answer 5

The force between two point charges is:
-proportional to each of the charges
-inversely proportional to the square of their distances apart.

F= k Qq/r^2

Question 6

Absolute electric potential

Answer 6

Absolute electric potential (V) is the work done on a unit charge in moving it to that point from a point remote from all other charges.

V is positive when Q is positive and force repulsive

Question 7

Electric Potential Difference

Answer 7

The energy needed to move a unit charge (work done)

Fd= Q change in V
Change in W=Q change in V

Question 8

Similarities between Electric Fields and Gravitational Fields

Answer 8

• Both have inverse square force laws
• Use of field lines/Use of equipotentj surfaces

Question 9

Differences between Electric Fields and Gravitational Fields

Answer 9

-Gravitational Field affects masses while electric field affects charges
-Gravitational force of attraction are insignificant at atomic level