P4- Circuit and Electricity Flashcards

1
Q

What is the symbol for Charge?

A

Q

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2
Q

What is the symbol for Current?

A

I

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3
Q

What is the symbol for time?

A

t

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4
Q

What is the equation for charge?

A

Q = I t (I x t)

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5
Q

What is the Pyramid for charge?

A

Q (charge) at the top, then I ( current) then t (time)

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6
Q

What is the difference between a battery and a cell?

A

A battery is a group of two or more cells. A cell is an individual component that provides the circuit with a source of potential difference.

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7
Q

Why are metals good electrical conductors?

A

Metals contain lots of free electrons that can move freely between the positively charged metal ions.

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8
Q

What is an electric current?

A

A flow of charge.

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9
Q

What is the flow of charge per second?

A

How quickly electrons are flowing through the circuit.

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10
Q

The size of the current is the……?

A

Rate of flow of charge

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11
Q

What is charge measured in?

A

C (coulombs)

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12
Q

What is current measured in ?

A

A (amps)

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13
Q

What is time measured in?

A

s (seconds)

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14
Q

What are the rules of a series circuit?

A
  1. Current is the same everywhere
  2. Potential difference is shared among the components ( it adds up to the potential difference of the power source)
  3. Resistance adds up.
  4. Components with a greater resistance will always have a greater share of the voltage.
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15
Q

What are the rules of a parallel circuit?

A
  1. They have more than one loop
  2. The potential difference across each branch is the same.
  3. When we add resistors in a parallel circuit, the more branches we add, the easier it is for the amount to flow. It decrease the overall resistance.
  4. The current in is split among the branches.
    EXTRA:
  5. If one component breaks the overall circuit will still work, because the current is still able to flow through other loops.
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16
Q

What is potential difference?

A

The force driving the flow of electrons around a circuit.

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17
Q

What is another name for potential difference?

A

Voltage

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18
Q

What are the units for potential difference?

A

V, volts

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19
Q

Which way does current (conventional current) flow around a circuit?

A

Positive terminal ——-> negative terminal

(Electrons travel in the reverse but we say they travel in this way)

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20
Q

Does an open switch allow or prevent current from flowing around a circuit?

A

It breams the circuit and so prevents current from flowing.

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21
Q

Define resistance

A

Everything that resists of opposes the flow of electrons in a circuit.

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22
Q

What does a current/voltage graph look like for a filament lamp?

A

An S shape

23
Q

V= I R

A

Voltage= current x resistance

24
Q

What does a diode do?

A

Only allow current ti flow one way around a circuit.

25
Q

What does a current/ voltage graph look like for a diode?

A

A straight line then vertically up.

26
Q

How does temperature effect resistance?

A

Increasing the temperature will increase resistance. Means it is harder for electrons to pass through the circuit.

27
Q

What does a current/voltage graph look like for a fixed resistor?

A

A straight line through the origin

28
Q

Why does increasing the temperature of a wire increase its resistance

A

At higher tempratures, the particles in the wire vibrate faster, which impedes(slows) the flow of electrons and therefore increasing the resistance.

29
Q

Define charge

A

A measure of the total current that flowed within a period of time.

30
Q

Formula for charge?

A

Charge= current x time

Q= I T

31
Q

Where can i learn symbols for electrical components?

A

Cognito.

32
Q

A light emitting diode will….

A

Emit light when the current flows through it and only allow current to flow in one direction.

33
Q

What do ammeters measure?

A

Current, and they are added to a circuit in series.

34
Q

What do voltmeters measure?

A

Potential difference(voltage)
They are added to a circuit in paralell.

35
Q

A resistor whose resistance decreases when temperature increases is a:

A

Thermistor

36
Q

Which type of resistor allows us to easily adjust its resistance?

A

Variable resistor

37
Q

A resistor which cannot vary the amount of resistance it provides is a:

A

Fixed resistor

38
Q

In which type of resistor does the resistance vary with light intensity?

A

Light dependent resistor (LDR)

39
Q

When the temperature increases, the resistance of a thermistor…

A

Decreases

40
Q

What are the three formulas for energy?

A
  1. Energy (E)= Power(p) x time(t)

E=Pt

  1. Energy(E)= Voltage(v) x current(I) x time (t)

E=VIt

  1. Energy (E)= Charge(Q)x Voltage (V)

E= QV
Charge is measured in coulombs

41
Q

What are the three formulas for power?

A
  1. Power(P) = Current (I) x voltage (V)

P= IV

  1. Power (P) = Energy (E) over Time (t)

P= E/t

  1. Power = Current squared X resistance

P=I squared x R

42
Q

Define static electricity

A

The build up of charge on insulating materials.

43
Q

How does static electricity build up?

A

When two objects are rubbed together, friction can cause electrons to move from one object onto the other. This can lead up to a build up of charge.

44
Q

Is static electricity more likely to build up on conductors or insulators?

A

Insulators because the electrons would just flow straight back if the materials were conductors.

45
Q

What causes a spark between an object and the earth?

A

A large build-up of charge on an object can cause a large potential difference between the object and the earth.

The large potential difference could allow electrons to jump through the air from one object to the other. We call this jumping of electrons a spark.

46
Q

What is an electric field?

A

An electric field is a region around a charged particle or object , within which a force would be exerted on other charged particles or objects.

47
Q

Do particles of the same charge attract or repel?

A

Repel

48
Q

Do particles of different charges attract or repel?

A

Attract.

49
Q

What are electric field lines?

A

Arrows that show the electric field around an object.

50
Q

What would a diagram of the electrical field lines around a positive particle look like?

A

All arrows perpendicular to the surface of the particle.

All arrows point away from the particle.

51
Q

If an object has a strong enough charge, what can it do to the surrounding air?

A

It can ionise the air

This means it causes the particles in the air to lose electrons so that they become charged. The air is then able to conduct electricity.

52
Q

What would a diagram of the electrical field lines around a negative particle look like?

A

All the arrows are perpendicular to the surface of the particle.

All arrows point towards the particle.

53
Q

What would a diagram of the electrical field lines between a positive and negative particle look like?.

A

Arrows point from positive to negative.