Topic 7 Flashcards Preview

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Flashcards in Topic 7 Deck (15):
1

Define electric current and state what this is in metals

Electrons flowing from the negative terminal to the positive terminal cell.
Packed together becoming ions releasing delocalised electrons

2

What type of current do cells and batteries provide?

Direct current

3

What will happen to the current if the P.D is increased?

Increases

4

How should you put an ammeter into a circuit?

Series with component

5

What does an ammeter measure?

Current or charge in amps

6

How do you put a voltmeter into a circuit?

In parallel to the component

7

What does a voltmeter measure?

P.D in volts

8

Define potential difference

Energy transferred per coulomb of charge that passes between 2 points in a circuit

9

Explain the effect of increasing resistance on the current

It decreases

10

What happens to the resistance of a filament lamp after it is turned on?
How does this affect current?

As the temperature increases, the resistance increases hence a curved graph

11

What happens to the resistance of a LDD as light intensity increases?
How does this affect current?

LDR high - little current
LDR low- lots of current

12

Explain what happens to a resistor as current passes through it

Friction caused by electrons colliding therefore current is reduced

13

State 3 ways of calculating power

Power=energy transferred / time taken
Power= current x P.D
Power= current*2 x resistance

14

What type of current does the mains supply provide?

Alternating current

15

Identify difference between AC and DC

AC- direction of current keeps changing due to generators rotating
DC- direction of movement stays the same