P4- Electric circuits Flashcards

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1
Q

How do some insulators become charged?

A

By rubbing another insulator on it

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2
Q

When a cloth was rubbed against a rod the cloth became positively charged, why?

A

Negatively charged electrons were transferred from the cloth to the rod. More positive charges on the cloth

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3
Q

How does a non contact force occur?

A

When two charged objects exert a force on each other

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4
Q

What happens to…
Same charges?
Dif charges?

A

Same changes repel
Dif charges attract

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5
Q

Switch
What does it do?
How does it look?

A

Enables current to be turned on and off
Two circles with diagonal line between

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6
Q

Cell
What does it do?
How does it look?

A

Pushed electrons around a circuit
Big line parallel to smaller line

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7
Q

Battery
What does it do?
How does it look?

A

More than one cell
A cell with dashed line between

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8
Q

Diode
What does it do?
How does it look?

A

Allows current to pass in the forward direction
Arrow in a circle

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9
Q

Fixed resistor
What does it do?
How does it look?

A

Reduced the current
Rectangle

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10
Q

Variable resistor
What does it do?
How does it look?

A

Allows current and resistance to be changed
Rectangle with arrow through it

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11
Q

Light emitting diode (LED)
What does it do?
How does it look?

A

Emits light when current passes through it in a certain direction
Diode with arrows off it

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12
Q

Lamp/bulb
What does it do?
How does it look?

A

Emits light when current passes through it
Circle with cross in it

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13
Q

Fuse
What does it do?
How does it look?

A

Melts and breaks circuit is current is too high
Rectangle with line through it

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14
Q

Voltmeter
What does it do?
How does it look?

A

Measure potential difference
Circle with V

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15
Q

Ammeter
What does it do?
How does it look?

A

Measures current
Circle with A

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16
Q

Thermistor
What does it do?
How does it look?

A

Resistance changes with temperature
Rectangle with hockey stick

17
Q

Light dependent resistor (LDR)
What does it do?
How does it look?

A

Resistance changes on amount of light
Rectangle in circle with arrows pointing to it

18
Q

Current?
Unit?

A

The flow of charge around a circuit
amps (A)

19
Q

Ammeter & voltmeter measures?
placed in?

A

Ammeter- Current, series
Voltmeter- Potential difference, parallel

20
Q

Resistance

A

Measure of how difficult it is for current to pass through a component

21
Q

Ohms law

A

The potential difference is directly proportional to the current when the temp is constant

22
Q

How to investigate the resistance of a wire based on length?

A

-Set up wire, ammeter & voltmeter in a circuit
-Attach a crocodile clip to start of wire and first specified length
-Record length, current & pd
-Switch of circuit, calculate resistance
-Vary length of wire, repeat

23
Q

What does a directly proportional graph look like?

A

Straight line through the origin

24
Q

How to investigate component characteristics

A

-Set up ammeter, variable resistor, component & voltmeter
-Record current and pd
-Switch off power supply
-Adjust resistance & take new reading
-After 5 readings, reverse terminals to take negative values
-Take another 5 readings, plot graph
-Repeat with other components

25
Q

Current-pd graph for a filament lamp

A

-Not an ohmic conductor
-As the pd increases, current and resistance increases
-If the temp increases, current and resistance increases

26
Q

Current-pd graph for a diode

A

-Not an ohmic conductor
-Current only flows in one direction
-In forward direction, as current increases, resistance increases

27
Q

Current-pd graph for themistors and LDRs

A

-Not ohmic conductors
-As temp or light intensity increase, resistance decreases

28
Q

In series circuit
Current is…?
Pd is…?
Resistance is…?

A

Same in each component
Shared between components
Added up across all

29
Q

In parallel circuit
Current is…?
Pd is…?
Resistance…?

A

Shared between branches
Same across all
Total res is less than the resistor with least resistance

30
Q

Series circuit
Components arranged in…
Routes?

A

Components arranged in a single chain
Current only has one route to take

31
Q

Parallel circuit
Components arranged in…
Routes?

A

Components arranged in branches
Current has more than one route to take