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A Level Physics > Electricity > Flashcards

Flashcards in Electricity Deck (15):
1

What is a coulomb?

One coulomb is the amount of charge which flows past a point when a current of one amp flows for one second

2

What is Kirchhoff's 1st law?

It states that the sum of the currents flowing into any point in on a circuit is equal to the sum of the currents flowing out of that point

3

What is a volt?

One volt is one joule per coulomb

4

What is electromotive force (emf)?

The energy transferred per unit charge when one other type of energy is converted into electrical energy

5

What is potential difference?

The electrical energy transferred per unit charge when electrical energy is converted into another form of energy

6

What is resistance?

The resistance of a component is the ratio of potential difference across the component to the current flowing through it

7

What is resistance caused by?

Resistance is caused by collisions between free electrons and the metal ions

8

What factors cause resistance to increase?

If the length increases, temperature increases, or cross sectional area decreases

9

What is Ohm's law?

For a conductor at constant temperature, the current in the conductor is proportional to the potential difference across it

10

Why does an increase in length of a wire cause increased resistance?

It increases the chance of collisions

11

Why does an increase in temperature cause increased resistance?

Higher temperature means the ions move more, increasing the chance of collisions

12

Why does increased cross-sectional area cause decreased resistance?

There are a greater number of possible routes for electrons to take and so there is a lower chance of collisions (cross sectional area is inversely proportional to resistance)

13

What is conventional current?

Flow of charge, opposite to electron flow

14

What is current?

Electric current is the flow of charged particles per unit time

15

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