P2.3 Flashcards

1
Q

What does static mean?

A

Still

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2
Q

What happens if a plastic is rubbed by a dry cloth?

A

~ The rod and cloth can become electrically charged
~ The plastic has an equal number of protons and electrons, as does the cloth
~ When rubbed some electrons from one can be transferred to the other which imbalances the charge on both of them

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3
Q

What do opposite charges do?

A

Attract

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4
Q

What do like charges do?

A

Repel

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5
Q

What are some examples of static electricity?

A

~ Balloons being rubbed on something and sticking to a wall
~ Van der graaf generator
~ Trampoline carpets

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6
Q

What charge does a gain of electrons give?

A

Negative charge

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7
Q

What charge does a loss of electrons give?

A

Positive charge

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8
Q

What does a voltmeter measure?

A

Voltage / potential difference

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9
Q

What does an ammeter measure?

A

Current (amps)

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10
Q

What does a fixed resistor do?

A

Lower the current, measured in ohms

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11
Q

What is a thermistor?

A

A heat sensor, used in thermostats

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12
Q

What are light dependent resistors used for?

A

Switching on circuits depending on whether there is light (like streetlights)

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13
Q

What can light emitting diodes be used for?

A

Making efficient lighting which only uses a little electricity but produces lots of light

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14
Q

What is electric current?

A

The flow of charge, measured with an ammeter

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15
Q

What is the measure of the large amount of electrons in an electric current?

A

1 coulomb

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16
Q

What is current a measure of?

A

The flow of coulombs per second

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17
Q

What does the letter I stand for?

A

Current (amps)

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18
Q

What does the letter Q stand for?

A

Charge (coulombs)

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19
Q

What is another word for potential difference?

A

Voltage

20
Q

What is potential difference?

A

Energy transferred per coulomb of charge

21
Q

What does work done mean?

A

Energy transferred

22
Q

What is the units of potential difference?

A

Volts

23
Q

What is work done/energy transferred measured in?

A

Joules

24
Q

As the current increases what else increases?

A

Potential difference

25
Q

Current is directly proportional to what?

A

The potential difference

26
Q

In series circuits, the total resistance is the sum of…

A

All the individual resistors or components

27
Q

In series circuits, the total potential difference of the cells is the sum of…

A

The individual cells

28
Q

In a series circuit the potential difference is shared between…

A

The components

29
Q

In series circuits, the current is…

A

The same throughout and through each component

30
Q

In parallel circuits, the potential difference across each component is…

A

The same

31
Q

In parallel circuits, the current is different…

A

In different branches of the circuit

32
Q

In parallel circuits, the total current through the whole circuit is the sum of…

A

The current through the separate components

33
Q

The higher the resistance…

A

The lower the current

34
Q

The higher the temperature…

A

The lower the resistance, so more current can flow

35
Q

A diode makes the current flow…

A

In only one direction

36
Q

Why does the current decrease when a conductor is heated?

A

~ Heat causes the free atoms/ions to vibrate more

~ Electrons collide more frequently which reduces the current

37
Q

What do electrically charged objects do when they’re brought together?

A

Exert a force on each other

38
Q

What is current a flow of?

A

Charge

39
Q

How can the resistance of a component be found?

A

By measuring the current through the components and the potential difference across the components

40
Q

What is the measure of resistance?

A

Ohms

41
Q

Why is the an increasing use of LEDs for lighting?

A

They use a much smaller current than other forms of lighting

42
Q

As the resistance of a light dependent resistor decreases…

A

The light intensity increases

43
Q

As the temperature of a thermistor decreases…

A

The temperature increases

44
Q

What are uses of LDRs?

A

~ Automatic lights
~ Camera shutter
~ Fridge lights

45
Q

What are uses of thermistors?

A

Heating systems

46
Q

What are uses of LEDs?

A

Efficient lamps