Chapter 4 🚨 Flashcards

(60 cards)

1
Q

Do you use ammeters in series or in parallel?

A

Series

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

In a parallel circuit, how do you calculate the total current?

A

The total current is the sum or the currents in the separate sections

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

In a parallel circuit what is important to remember about the potential difference across each component?

A

It is the same

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

In a parallel circuit, bigger the resistance…

A

The smaller the current

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How to calculate current using potential difference and resistance?

A

Current = potential difference/ resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

When you add more resistors in a parallel circuit, why does the total resistance decrease?

A

The total potential difference is the same, so the total current increases. The total resistance = pd/current, so this means the resistance is less

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

In a series circuit, what is important to remember about the current?

A

The current passing through each component is the same

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How do you calculate the total potential difference of a series circuit?

A

Add up the potential differences of all the components

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How to calculate the total potential difference of cells in a series circuit

A

Add up the potential difference of each cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How to find the total resistance in a series circuit?

A

Add up the resistance of each component

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

When you add more resistors in a series circuit, why does the overall resistance increase?

A

The total potential difference is shared across more resistors, giving each one less. This means that the current decreases, and as the total pd doesn’t change, this means that the total resistance is greater than before

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How to calculate resistance using pd and current

A

Resistance = pd/current

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is a diode?

A

A non ohmic conductor

Only lets current flow in one direction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is a light emitting diode?

A

Emits light when current flows through it in a forward direction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is a thermistor?

A

Temperature dependent resistor

Resistance decreases when temperature increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Why are ammeters connected in series?

A

So the current across them and the component is the same

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Is a voltmeter wired in parallel or series?

A

Parallel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Why is a voltmeter connected in parallel?

A

So it measures the potential difference across it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is resistance?

A

Resistance is when the electrons travelling around the circuit have go push through the ions in the metal filament

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How to calculate resistance using potential difference and current

A

Resistance (ohms) = potential difference/current

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the current through a resistor directly proportional to?

A

The potential difference across the resistor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is Ohm’s law?

A

The current through a resistor at constant temperature is directly proportional to the potential difference

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Function of cell

A

Pushes electrons around a complete circuit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Function of switch

A

Enables current to be turned on and off

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Function of bulb
To indicate when a current is passing through the circuit
26
What is an ammeter?
Used to measure electric current
27
Function of fixed resistor
Limits current in circuit
28
Function of variable resistor
Allows current to be varied
29
Function of fuse
Melts to break circuit when current is too high
30
Function of heater
Used to transfer energy from an electric current to heat surroundings
31
function of voltmeter
Measures voltage (potential difference)
32
How to calculate charge flow using current and time
Charge flow = current x time
33
What is the name for a charged atom?
An ion
34
What happens when an object becomes charged?
It loses or gains electrons
35
Which type of forces attract?
Opposites
36
What is a charged atom called
An ion
37
How to objects become hatched by friction
Electrons are transferred
38
Where is an electric field strongest
Nearest to it
39
Which direction do electric field lines go in
Positive to negative
40
What happens to cause a spark
When there is a high PD between an object and an earthed object High PD = strong electric field This pulls electrons out of air molecules This makes air conductive so a current can flow through causing a spark
41
What does the voltage of a battery tell you
How much energy it transfers to each coulomb of charge
42
What is the direction of current
Positive to negative
43
Why is a wire an ohmic conductor
It’s resistance stays constant
44
Why does increased temperature increase resistance
The atoms are vibrating more so they resist the passage of the electrons
45
Why is a diode a non ohmic conductor
The current isn’t directly proportional to the PD
46
What happens to the resistance of an LDR if the light intensity increases
It decreases
47
Where does the current go in a series circuit
Through each component
48
What happens to the PD in a series circuit
It is shared between the components
49
What is the total PD of cells in a series circuit
The sum of all the PDs
50
How to calculate resistance in series
Add the sums of all the resistances together
51
Why does adding more resistance in series increase the total resistance
The current through the resistors is less and the PD is unchanged
52
How to find the total current in a parallel circuit
The sum of the currents through the separate branches
53
What is the PD of components in parallel
The same
54
How to work out total resistance in parallel
R1 x R2 ——— R1 + R2
55
potential difference of live wire
230 V
56
potential difference of people
0V
57
why do you get an electric shock when you touch live wire?
wire = 230 V we = 0V large potential difference between us and wire so charge passes through us
58
What is current?
A flow of electrical charge
59
What is he potential difference?
The pushing force which drives the charge around the circuit
60
How does rubbing a rod with a cloth cause it to become charged?
There is friction between the two This causes electrons to move from the objects Which leaves the charge on one positive And the other negative