Electric Fields

Question 1

Electric Charge

Answer 1

A property of matter that causes the particles or objects that possess it to experience a force when near other objects or particles that also possess it. Electric charge is conserved.

Question 2

Positive Charge

Answer 2

Too few electrons.

Question 3

Negative Charge

Answer 3

Too many electrons.

Question 4

Electric Force

Answer 4

Attractive or repulsive force caused by electric charge.

Question 5

Electrically Neutral

Answer 5

An object with equal amounts of positive and negative charge.

Question 6

Conductors

Answer 6

Materials such a metals which contain a lot of free electrons.

Question 7

Insulators

Answer 7

Materials that do not allow the flow of free electrons.

Question 8

Earthing (or grounding)

Answer 8

The process by which the conductor empties its charge to the ground and becomes electrically neutral.

Question 9

Electric Field Lines

Answer 9

The lines which positive charges follow. the extend aways from the positive charge and towards the negative charge.

Question 10

Electric Field Strength

Answer 10

The force per unit charge at a point. Given in N/C.

Question 11

Uniform Field

Answer 11

The electric field strength is the same at all positions in the field.

Question 12

Non-Uniform Field

Answer 12

The electric field strength varies with position in the field

Question 13

Electric Dipole

Answer 13

Two equal and opposite charges separated by a distance.

Question 14

Electric Potential

Answer 14

The potential energy per unit charge of a positive test charge placed at a point in an electric field. It is a property of the field itself, whether or not a charged object has been placed in in it (measured in J/C=V).

Question 15

Electric Potential Energy

Answer 15

The energy of a charged object in an electric field (measure in J).

Question 16

Equipotentials

Answer 16

Lines of constant potential perpendicular to the field lines. Evenly spaces equipotentials gives a uniform field. Unevenly spaced equipotentials gives a non-uniform field.

Question 17

Potential Gradient

Answer 17

The change in potential per unit distance at a point in a field (given in V/m)

Question 18

Dielectrics

Answer 18

Insulating materials used to increase the capacity of the plates of a capacitor to store charge for a fixed potential difference. When a dielectric is placed between the charged plates, its molecules become polarised.

Question 19

Relative Permittivity (or dielectric constant)

Answer 19

The ratio of charge stored with dielectric to charge stored without dielectric.

Question 20

Capacitance

Answer 20

The charge stored per unit p.d. applied across the plates of a capacitor.