Flashcards in Electricity - Paper 1 Deck (38)

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1

## Draw the circuit symbol for a lamp

### an X in a circle

2

## Draw the circuit symbol for a diode

### An arrow head in a circle

3

## Draw the circuit symbol for a resistor

### A rectangular box

4

## Draw the circuit symbol for a variable resistor

### A rectangular box with a diagonal arrow

5

## Draw the circuit symbol for an LED

### Same as a diode with 2 arrows points away

6

## Draw the circuit symbol for a fuse

### A rectangular box with a horizontal one running through it

7

## Draw the circuit symbol for a voltmeter

### V in a circle

8

## Draw the circuit symbol for an ammeter

### A in a circle

9

## Draw the circuit symbol for a thermistor

### a rectangular box with a diagonal line through it

10

## Draw the circuit symbol for an LDR

### A rectangular box in a circular with 2 arrows pointing towards it

11

## Define Current

### Flow of charge (electrons) measured in amps (A)

12

## State the equation that links charge, current and time.

###
Charge = Current x time

Q = It

13

## What are the units of charge

### Coulombs (C)

14

## What is the relationship between current and resistance?

### As resistance increases, current decreases and vice versa

15

## State the equation that links potential difference, current and resistance

###
Potential difference = Current x resistance

V = IR

16

## State the units of potential difference

### Volts (V)

17

## State the units of resistance

### Ohms

18

## State the relationship between the length of wire and its resistance.

### As the length of the wire increases the resistance increases. they are directly proportional

19

## As more resistors are added in series what happens to the total resistance.

### Total resistance increases (Rt = R1 + R2 + .....)

20

## State ohms law

### Current is directly proportional to potential difference constant temperature. this means resistance remains constant.

21

## Sketch the I/V graph for a resistor

### A straight line through the origin (current and potential difference are directly proportional - an ohmic conductor)

22

## Sketch the I/V graph for a bulb

### It starts off as a straight line through the origin but the the current levels offs so the graph curves. Non ohmic conductor

23

## How does the resistance of a lamp change as it heats up?

### As temperature increases resistance increase. Atoms/ions have more energy so vibrate more taking up more space making it harder for electrons to travel down the wire.

24

## Sketch the I/V graph for a diode

### Current can only flow in one directions. So zero current in the negative direction but in the positive direction current increases slightly after the origin. Non ohmic conductor

25

## State the relationship between temperature and resistance for a thermistor

### As temperature increases resistance decreases.

26

## State some uses of thermistors

### In thermostats to turn circuits on/off if they get too hot to cold e.g. in an iron, hair straighteners etc

27

## State the relationship between temperature and light intensity for a LDR

### As light increases increases, resistance decreases

28

## State some uses of LDRs

### In circuits to switch lights on when it gets dark

29

## state the rules for current, potential difference and resistance in a series circuit

###
Current - same flowing through each component

Potential difference - the p.d. of the power supply is shared between the other components

Resistance - the total resistance increases as more components are added. the total resistance is the sum of all the individual components resistance

30