P4 - Electrical Circuits Flashcards Preview

AQA GCSE Physics > P4 - Electrical Circuits > Flashcards

Flashcards in P4 - Electrical Circuits Deck (17)
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1

What is a battery?

2 or more cells joined together.

2

Ohm’s law?

Current through a resistor at a constant temp is directly proportional to the potential difference across the resistor.

3

Reversing the potential difference through a resistor....

Reversed the current through it.

4

Why do insulating materials become charged?

because electrons are transferred

5

D. Current

Flow of charge

6

What is electric charge measured in?

coulombs

7

D. Diode?

a non-ohmic conductor that has a much higher resistance in one direction then the other so allows current only one way.

8

1 Amp is....

I coulomb/second

9

Why are voltmeters connected in parallel?

So that it measures the voltage across something/a component

10

Current is directly proportional to....

resistance

11

D. Thermistor

A temperature-dependant resistor, temp increase = resistance decrease

12

E. Total resistance for a series circuit

T.R = R1+R2+R3 etc

13

E. Total resistance for a parallel circuit?

1/t.r = 1/R1 + 1/R2

14

In a series circuit?.... (current and P.D)

Current is the same everywhere, P.D is shared equally through the components

15

In a parallel circuit....

Current is split and P.D is the same everywhere?

16

Putting more resistors in parallel....

Decreases total resistance of circuit because total current through them is increased and P.D is unchanged

17

Why does a filament lamp's resistance change as P.D changes?

Because as P.D increases the temp increases, so the metal ions have more k.energy and vibrate more vigorously and so it is harder for the electrons to pass through them, which means that the resistance is increased.