Physics chapter 4

?
  • Created by: abiiwelsh
  • Created on: 22-06-18 20:02
Do insulators or conductors become charged by friction?
Insulators
1 of 39
Why do charged objects exert non- contact force on each other?
Charged objects have electric field, when another charged object in the field it experiences a force
2 of 39
For a positively charged object, which way are the lines of force pointing?
Away from object (always imagine it is another positively charge object in the electric field)
3 of 39
For a negatively charged object, which way are the lines of force pointing?
Towards the object (always imagine it is a positively charged object in electric field)
4 of 39
What happens to air molecules if there are oppositely charged objects?
Air molecules experience force- move towards positively charged
5 of 39
What happens to air molecules if field between charged objects is too strong?
Sparking- electrons pulled from air moleclues by force- knock on effect- sudden flow of electrons
6 of 39
What is the purpose of circuit diagram?
Shows how components in circuit connect
7 of 39
What is a current?
Flow of charge
8 of 39
What is the size of the current?
The rate of the flow of electric charge
9 of 39
In series circuit is the current, at different points, different or always the same?
Always the same- same number of electrons passing point per second
10 of 39
What is electric charge measured in?
Coulombs (C)
11 of 39
What is current measured in?
Amperes (A)
12 of 39
When the rate of flow of charge is 1 coulomb/ second, what is the current?
1A
13 of 39
What is the formula for charge flow if there is a constant current?
Charge flow (C)= current (A) x time taken (s)
14 of 39
What is 1mA (milliamperes) equal to?
0.001A
15 of 39
Is the ammeter connected in series or parallel with component?
Series- same current everywhere in one series
16 of 39
What is potential difference?
Energy transferred to component or work done on component per coulomb
17 of 39
Is voltmeter connected in series or parallel with component?
Parallel
18 of 39
What is the formula for potential difference?
Potential difference (V)= energy transferred (J) / charge (C)
19 of 39
What is the formula for resistance?
Resistance (ohms) = potential difference / current
20 of 39
What happens to current when resistance increases?
Current decrease
21 of 39
How are current and potential difference related?
Directly proportional
22 of 39
What is ohms law?
The current through a resistor at constant temperature is directly proportional to potential difference across resistor
23 of 39
What is an ohmic conductor?
Component with constant resistance even if current changes (constant temp.)
24 of 39
What is an example of an ohmic conductor?
Wire
25 of 39
How do you work out resistance from current- potential difference graph?
The gradient- always constant because current and potential difference are directly protportional
26 of 39
Give an example of non- ohmic conductor.
Filament bulb- current and potential difference are not directly proportional so the resistance is dependent on the current- as current increases, resistance does + diode- when potential difference is over 0 (not in reverse), the current increases.
27 of 39
Why does a filament bulb fail when you turn it on?
Sudden big current passes- burns
28 of 39
What are light emitting diodes (LED) for?
Indicators for devices. Eg charging device- shows there is current flowing
29 of 39
What is a thermistor?
Temperature dependent resistor- temperature increase, causes resistance decrease
30 of 39
What is a light dependent resistor?
LDR- resistance decrease if light increase
31 of 39
What is the potential difference of the cell?
Measure of energy from cell to each electron
32 of 39
In series circuit is the total potential difference from power supply the same for each component or shared between components?
Shared- the energy is transferred from electrons to component and used up so other component has to use rest of energy
33 of 39
In series is the total resistance the same in each component or the sum of resistance of each component?
The sum of each resistance
34 of 39
In parallel is the total current the same as each components current or the sum of each component on different branches?
It is the sum
35 of 39
In parallel, is the potential difference across each componant the same or different?
The same- electrons pass through both components, delivering same amount of energy from cell
36 of 39
What is the formula for current of each component?
Current = potential difference / component resistor
37 of 39
What happens to resistance in series when you increase number of resistors?
Total resistance increases- PD of each component decreases so current decreases, but total potential difference is still the same so same PD / smaller current = bigger TOTAL resistance
38 of 39
What happens to resistance in parallel when you increase number of resistors?
Decrease total resisitance- each branch has total potential difference- require more current to supply potential difference to another resistor, the same total PD / bigger current = smaller total resistance
39 of 39

Other cards in this set

Card 2

Front

Why do charged objects exert non- contact force on each other?

Back

Charged objects have electric field, when another charged object in the field it experiences a force

Card 3

Front

For a positively charged object, which way are the lines of force pointing?

Back

Preview of the front of card 3

Card 4

Front

For a negatively charged object, which way are the lines of force pointing?

Back

Preview of the front of card 4

Card 5

Front

What happens to air molecules if there are oppositely charged objects?

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Physics resources:

See all Physics resources »See all Electricity resources »