Electrical quantities Flashcards

Mr. Rocha

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1
Q

Does the current flow from negative to positive or positive to negative?

A

positive to negative

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2
Q

Does the electron flow flow from negative to positive or positive to negative?

A

negative to positive

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3
Q

1 Ampere =

A

1 coulombs of charge per second

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4
Q

What is the unit and symbol for charge?

A

unit: coulomb
symbol: C

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5
Q

What is the unit and symbol for current?

A

unit: amp
symbol: A

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6
Q

Define voltage

A

the work done by charge passing through an electrical component

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7
Q

What is the unit for voltage?

A

volts

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8
Q

What is voltage measured by?

A

voltmeter

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9
Q

What happens if there is an ‘obstacle’ in the middle on a current?

A

particles waste energy going past it

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10
Q

Define EMF (electromotive force)

A

textbook definition:
the electrical work done by a source, move unit of charge around circuit: the voltage across the terminals of a source

simpler: the amount of energy provided by a power source (like a battery) to each unit of charge as it moves through a circuit. It’s like the “push” or force that makes electric charges flow around the circuit.

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11
Q

If cells with EMFs E1 & E2 are connected in series, their combined EMFs are given by:

A

E = E1 + E2

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12
Q

What does P.D. mean?

A

potential difference

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13
Q

1 volt =

A

1 J of energy to move 1 coulomb of charge

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14
Q

When a symbol has an arrow through it, this indicates that…

A

it’s variable

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15
Q

Describe ohmic resistor

A

has a constant resistance; its current-voltage characteristic is a straight line graph, so that the current through it is directly proportional to the voltage across it. can keep the temp. constant, so the current can easily increase as the voltage increases (constant resistance)

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16
Q

Describe the graph

A

resistor has a constant resistance. current-voltage characteristic is a straight line graph, so that the current through it is directly proportional to the voltage across it

17
Q

Describe the graph

A

at higher voltages, the graph starts to curve over. the current increases more and more slowly as the voltage is increased. current is not proportional to voltage

18
Q

Which has a higher resistance? Why?

A

B because its current increases slower than resistor A when potential difference (voltage) increases

19
Q

Define variable resistor

A

a resistor where resistance can be changed, for example, by turning a knob or moving a slider

20
Q

What are the 3 different types of resistors?

A
  • variable resistor
  • LDR
  • thermistor
21
Q

Define LDR

A

a type of resistor whose resistance depends on the amount of light falling on it

22
Q

Define thermistor

A

a type of resistor whose resistance depends on its enviornment

23
Q

What is Kirchhoff’s first law?

A

the total current going in to a junction in a circuit is equal to the total current going out of the junction

24
Q

What is Kirchhoff’s second law?

A

The sum of the EMFs around an closed loop in a circuit is equal to the sum of the p.d. in that loop