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Flashcards in P2: electricity Deck (39)
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1

Define electricity

The motion of charged particles

2

How does an object become charged?

For something to become charged it has to gain or loose electrons

3

Why do charge objects attract or repel?

Charged objects attract or repel because they create electric fields around themselves

4

How is lightning made?(4):

-clouds become negatively charged due to friction from hail.
-this repels electrons on the ground, revealing the protons
-electrons try to move to the ground, those who have create a path for other electrons
-this creates heat and light,which is lightning

5

What fuels a circuit?

The fuel in a circuit is the battery/cell , the ENERGY it provides is measured in JOULES

6

charge(3):

Measured in coulombs (c)
Charge= current(a) x time(s)
(Q=I X T )

7

Define potential difference

The energy transferred per unit charge
PD= energy(j)/charge(c)

8

Define current

The speed at which they move around, measured in AMPS (A)

9

Define resistance(2):

- The measure of how much the current is slowed down by components in a circuit
- Resistance(Ω)= current (a) / potential difference (v)

10

Electricity is ...

Always trying to find the fastest route to the ground

11

What is ohms law?

Ohm’s law states that the current through a conductor is directly proportional to the voltage across two points.

12

Overhead and under ground cables(6):

Overhead:
+ easier to fix + does not require a cooling system + could fall - ugly
Underground :
+ electricity won’t shock anyone
- requires cooling system (expensive)

13

Series circuits(2):

-CURRENT IS THE SAME
- POTENTIAL DIFFERENCE IS SHARED

14

Parallel circuits(2):

- CURRENT IS SHARED
- POTENTIAL DIFFERENCE IS THE SAME

15

What is the purpose of the fuse?

If for any reason the voltage gets too high the thin wire in the fuse will snap and melt, cutting the circuit

16

What is the mains electricity?

230V

17

What is the equation of power?

Power= voltage x current
P= V X I

Power= (current)^2 x resistance
P= I ^2 x R

Power = Work done / time
P= W/t

18

The national grid(5):

Power station-step up transformer-pylons and cables-step down transformer-house

19

Power:

P= energy(j)/time(s)

20

Direct current:

Flow of electric charge in only one direction

21

Alternating current:

Electric current continually changes direction

22

Live wire(2):

- Brown
-Conducting wire connection that carries the alternating current

23

Neutral wire(3):

- Blue
-Conducting wire connection that allows electrical charge to its return source
- Completes the circuit

24

The National Grid (definition):

A network of cables and transformers that links power stations to consumers across the country

25

Why are the outer castings of plugs made from plastic?

This is because plastic is an insulator and does not conduct electricity

26

Step-up transformers:

Transformers that changes an alternating potential difference across the primary coil to a higher potential difference across the secondary coil

27

Step-down transformers:

Transformers that changes an alternating potential difference across the primary coil to a lower potential difference across the secondary coil

28

Ammeters are connected in...

Series

29

Voltmeters are connected in...

Parallel

30

In any Ohmic resistor the resistance...

stays constant