Chapter 8

Question 1

What is the SI units for electric current

Answer 1

Amperes(A)

Question 2

What is electric current defined as?

Answer 2

Electric current is defined as the rate of flow of charge

Question 3

What is the equation linking

• Current
• Charge
• Time

Answer 3

Q = I x t

Question 4

What is the SI unit for charge

Answer 4

Coulombs

Question 5

What is current derived from the equation Q = It

Answer 5

The amount of charge passing a given point in circuit per unit time

Question 6

What is 1A equal to

Answer 6

1 C/s

Question 7

What type of property is electric charge

Answer 7

A physical property

Question 8

What are the 2 types of charges

Answer 8

1) Positive

2) Negative

Question 9

What are ions described as when they referred by their charges

Answer 9

Relative charges

Question 10

What is e

Answer 10

Elementary Charge

Question 11

What is Elementary Charge

Answer 11

The relative charge a proton has e
(A electron has a charge of
-e)

Question 12

What is the value of e

Answer 12

1.60 x 10^-19C

Question 13

What is net charge

Answer 13

the charge on the object which is due to its gain or loss of electrons

Question 14

How do you calculate the net charge on a object

Answer 14

Q = ne

Q-Coulombs
n-Number of electrons
e-Elementary charge

Question 15

What is a charge carrier

Answer 15

carriers of charge(lol)

Question 16

Name 2 charge carriers and where they operate

Answer 16

Electrons - Metals

Ions - Liquids

Question 17

What is one way to make electrons to move in a metal wire

Answer 17

to make a positive end- this means all the electrons will flow towards to this direction

Question 18

The greater the the rate of charge flow

Answer 18

the greater the electric current in a wire

Question 19

What may a large current be due to?

Answer 19

1) A greater number of electrons moving past a given point each second
(e. g. a wire with a greater cross-sectional area)

2)A increase in the speed of the electrons moving faster through the metal

Question 20

What is Conventional current

Answer 20

The direction of the electric current from the positive terminal to negative terminal

Question 21

What is electron flow

Answer 21

The direction of the electric current from the negative terminal to the positive terminal

Question 22

What is the name of the liquids that can carry current

Answer 22

Electrolyte

Question 23

What are all the electrolyte

Answer 23

Molten ionic compounds
or
Ionic solution

Question 24

What is the positive and negative electrodes called

Answer 24

1) Cathode(-)

2) Anode(+)

Question 25

What is an ammeter used for

Answer 25

To measure the electric current at any point in a circuit

Question 26

How much resistance does an ammeter have

Answer 26

Very little resistance

so it does not affect the current

Question 27

Is the ammeter in parallel or in series

Answer 27

series

Question 28

What does the conservation of charge state

Answer 28

That electric charge cannot be created nor destroyed

Question 29

What does Kirchhoff’s first law states

Answer 29

For any point in an electrical circuit, the sum of currents into that points is equal to the sum of currents out of the circuit

Question 30

What is number density

Answer 30

It is the number of free electrons per cubic metre of material.

Question 31

What does a higher number density mean

Answer 31

The greater the number density the better the electrical current

Question 32

What are the 3 types of number density classification

Answer 32

1) Insulators
2) Semi-conductors
3) Conductors

Question 33

What is the value of number density for conductors

Answer 33

Y x 10^28m-3

Question 34

What is the value of number density for semi-conductors

Answer 34

Y x 10^17m-3

Question 35

Why does appliances turn on instantly

Answer 35

This due to all the free electrons in the wire moving almost instantly

Question 36

What is the equation linking

• Current
• Mean drift velocity
• Elementary Charge
• Number of electrons
• Cross sectional area

Answer 36

I = A x n x e x v

Question 37

What is mean drift velocity

Answer 37

The average velocity gained by the free electrons of a conductor, with which the electrons get drifted under the influence of an electric field

Question 38

What affect does the Cross sectional area of a wire have in the drift velocity

Answer 38

the smaller the Cross sectional area the higher the mean drift velocity