P3.1 - Static and Charge Flashcards Preview

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Flashcards in P3.1 - Static and Charge Deck (23)
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1
Q

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A

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2
Q

Why are atoms neutral?

A

they have an equal amount of protons and electrons

3
Q

how do you produce static electricity (and explain what it is)? (3 marks, 4 points)

A

1) Rub two insulators together
2) Electrons are transferred between both insulators
3) One object object ends up with a surplus of electrons, other a surplus of protons
4) which creates a corresponding charge difference (which is static electricity)

4
Q

How do you discharge a charged object?

A

+ connect it to something that allows the charge to flow
ie. a piece of metal or when you touch a car door

5
Q

What is a spark?

A

A flow of charge (when a object becomes discharged)

6
Q

What is a gravitational field?

A

a region around a mass where another mass experiences a force

7
Q

Describe field lines (3 points)

A

+ are like elastic bands, will stretch when a charged object is placed in the field lines
+ force on an object will be in the direction that causes field lines to shorten
+ close = strong field

8
Q

What is current?

A

The rate of flow of charge

9
Q

What are the conditions for a current to flow? (2)

A

+ need a cell or battery/ power supply
+ current everywhere in a closed loop is the same

10
Q

Which way does a current flow?

A

From the positive terminal of the battery to the negative

11
Q

What is the equation to calculate charge?

A

charge flow (C) = current (A) x time (S)

12
Q

What is charge measured in?

A

Coulombs (C)

13
Q

What is current measured in?

A

Amperes/amps (A)

14
Q

how do objects become charged?

A

lose or gain electrons

15
Q

what happens when there is difference in charge (positive vs negative)between two objects?

A

potential difference occurs (rapid transfer of charge), known as static electricity

16
Q

what is required for an uncharged object to become charged by induction?

A

electrons to move around the object

17
Q

what is the direction of an electric field?

A

the direction that a positively charged object would move at that point in the field

18
Q

what is a conventional current?

A

The model where current flows from positive to negative terminals on a circuit(opposite to electron current flow)

19
Q

what are small currents measured in?

A

miliAmps (mA)

20
Q

what are currents of home appliances measured in?

A

mA (so 1000Amps is a lot, 1kA)

21
Q

why do electrons flow in the direction they do?

A

negative -> positive
because they’re negatively charged

22
Q

in what kind of objects does static electricity build up?

A

only in insulators

23
Q

what are the conditions needed for charge to flow? (2)

A
  • source of potential difference
  • closed circuit