P5.2 - Electrical quantities

Question 1

Objects become charged when

Answer 1

they gain or lose electrons

Question 2

Charge is measured in

Answer 2

Coulombs (C)

Question 3

An objective can be either

Answer 3

negatively or positively charged

Question 4

Two positive or two negative charges will

Answer 4

repel

Question 5

Two opposite charges will

Answer 5

attract

Question 6

When there is a difference between positive and negative charge of two objects it is called

Answer 6

potential difference

Question 7

potential difference causes

Answer 7

a rapid transfer of charge known as static electricity in which a spark is produced

Question 8

Suggest why clothes dried in a tumble drier might stick to each other.

Answer 8

The clothes will rub against each other which would charge the clothes as electrons are lost when the clothes rub together. Some will lose electrons and become positively charged and others will gain electrons and become negatively charged. The clothes that are oppositely charged will attract each other and stick together.

Question 9

Rubbing an object against another object will cause

Answer 9

electrons to jump from one object to another causing charges to form between both objects

Question 10

Substances that allow electric charge to pass through are called

Answer 10

electrical conductors (all metals are electrical conductors)

Question 11

Substances that do not allow electric charge to pass through are called

Answer 11

electrical insulators (glasses and plastics)

Question 12

When you charge an object with static electricity you are

Answer 12

adding or taking away negatively charged electrons so the charge on the object becomes unbalanced

Question 13

Example of change in charges

Answer 13

when you rub glass or a rode with cloth the electrons from the rod are rubbed onto the cloth so the cloth becomes negatively charged and the rod becomes positively charged

Question 14

What is electrostatic forces

Answer 14

an attraction or repulsion due to electric charges.

Question 15

Charged objects create

Answer 15

invisible electric fields around them

Question 16

If another electrically charged object enters an electric field the charge will feel a

Answer 16

force acting on it

Question 17

The strength of the force of an electric field depends on

Answer 17

how close the particles are: the closer the larger the force

how much electrical charge they carry: the more charge the larger the force

Question 18

If a positive point charge exerts an electric field the direction will

Answer 18

be going away from the positive charge

Question 19

If a negative point charge exerts an electric field the direction will

Answer 19

be going towards the negative charge

Question 20

Electrical current is the

Answer 20

flow of electric charges

Question 21

Electrical current is measured in

Answer 21

amps (A)

Question 22

Conventional current flows from the

Answer 22

positive end of the battery to the negative end.

Question 23

electrons flow from the

Answer 23

negative end of a battery to the positive end of the battery because they are negatively charged

Question 24

current =

Answer 24

charge/time (I = Q/t)

Question 25

Electrical insulators have no free

Answer 25

electrons so no charge can carry a current

Question 26

electrical conductors have lots of

Answer 26

charges that a free to move, which in metals are electrons.

Question 27

Potential difference (p.d) is measured in and by

Answer 27

volts (V) and voltmeter

Question 28

electromotive force (e.m.f) measures

Answer 28

the amount of energy a energy source supplies to each charge passing through. (for example: a mobile phone battery provides an e.m.f of 3.8V to drive current through the phones circuit)

Question 29

(e.m.f) is measured in

Answer 29

volts

Question 30

potential difference (p.d) is the difference in

Answer 30

the amount of energy that charge carriers have between two points in a circuit

Question 31

voltage =

Answer 31

amount of energy transferred / charge (V = E/Q)

Question 32

Ammeters measure

Answer 32

the flow of current that passes through

Question 33

Voltmeters measure

Answer 33

p.d between two points in circuit

Question 34

Resistance is the measure of

Answer 34

how difficult it is for currents to flow through a compotent

Question 35

charge flow is affected by

Answer 35

1. The resistance: if resistance increase current decrease

2. The p.d: if p.d increase current increase

Question 36

Resistance measured in

Answer 36

ohms (Ω)

Question 37

what is ohms law

Answer 37

resistance between two points in circuit is equal to p.d between two points divided by current flowing through them. R = V/I

Question 38

The resistance of a component can be found using a

Answer 38

circuit by placing the component (lamp or resistor) in a circuit with an ammeter to measure current and voltmeter to measure p.d.

Question 39

a voltage current graph for a component where the resistance remains same shows a

Answer 39

direct proportion between p.d and current. This is ohmic resistor

Question 40

For a particular conductor the resistance is

Answer 40

proportional to the length. The longer the conductor the further the electrons have to travel and the more likely they collide with metal ions meaning more resistance. A wire twice as long will have twice as much resistance

Question 41

Resistance can be shown in a model of a conductor

Answer 41

as the electrons which represent the flow have to get passed the metal ions in which they collide causing resistance

Question 42

Resistance is inversely proportional to the

Answer 42

cross sectional area of a wire. The greater the cross sectional area of a conductor the more electrons there are to carry charge along donators length so decrease resistance. Twice the cross sectional area half the resistance.