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Physics Section 3: Current Electricity > Current, Potential Difference And Resistance > Flashcards

Flashcards in Current, Potential Difference And Resistance Deck (20)
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What is current

Rate of flow of charge

1

Give an example do current in a wire

Like WATER flowing in a PIPE
The amount of water that flows depends on the flow rate and the time

2

What is the equation linking current to charge and time

I=Q/T

3

What direction does conventional current flow

From + to -
The OPPOSITE way from ELECTRON flow

4

What is one coulomb defined as

The amount of CHARGE that passes in 1 SECONDS when the CURRENT is 1 amperes

5

What is the potential difference defined as

Energy converted per unit charge moved

6

To make electric charge flow through a conductor what do you need to do on it

Work

7

What is the pd in the water analogy

The pressure that's forcing water along the pipe

8

What is the equation linking voltage to energy and charge

V=W/Q

9

When is the potential difference across a component 1 volt

When you convert 1 joule of energy moving 1 coulomb of charge through the component

10

How much current you get for a particular pd depends on heat

The resistance of the component

11

What can you think of a components resistance as

A measure of how DIFFICULT it is to get a CURRENT to FLOW through it

12

What is the equation which links resistance to voltage and current

R=V/I

13

When does a component have a distance of 1

If it's pd of 1V makes a current of 1A flow through it

14

For an ohmic conductor what is constant

The resistance

15

What is ohm's law

Provided the TEMPERATURE is constant, the CURRENT through an ohmic conductor is DIRECTLY proportional to the PD across it

16

What are the conductors which obey ohms law called

Ohmic conductors (mostly metals)

17

What does the graph of an ohmic conductor show when you plot voltage against current

Straight line (origin)
Double pd double current- directly proportional
Resistance constant - gradient always fixed

18

What will have a significant effect on resistance (resistivity changes)

Light level
Temperature

19

What is internal resistance

Loss of pd per unit current