Electricity

Question 1

What is the equation linking charge current and time

Answer 1

Q=It

Question 2

What is the symbol and units for charge

Answer 2

Q, coulombs

Question 3

What is the symbol and units for current

Answer 3

I, amps

Question 4

What is the symbol and units for time

Answer 4

T, seconds

Question 5

What is the symbol and units for voltage

Answer 5

V, volts

Question 6

What is the symbol and units for resistance

Answer 6

R, ohms

Question 7

What is the symbol and units for power

Answer 7

P, watts

Question 8

What is the symbol and units for energy transferred

Answer 8

E, joules

Question 9

What is the equation for energy transferred, using E, V, I, t

Answer 9

E= VIt

Question 10

What is the equation for energy transferred using Q, V and E

Answer 10

E=QV

Question 11

What is the equation for resistance

Answer 11

R=V/I or V=RI

Question 12

When the resistors are in series how do get the R-total

Answer 12

R-total=R1+R2

Question 13

When the resistors are in parallel what is the R-total

Answer 13

The R-total is less than either resistor on its own

Question 14

What is resistance

Answer 14

how difficult it is for the charges to flow through an electrical component

Question 15

What two factors effect resistance of a wire

Answer 15

Thickness and length

Question 16

How does the length of the wire effect the resistance

Answer 16

Longer the wire, higher the resistance

Question 17

How are the length of the wire and resistance related

Answer 17

The resistance is directly proportional to the length

Question 18

How does the thickness of the wire effect the resistance of the wire

Answer 18

The thicker the wire the lower the resistance

Question 19

How is the current and voltage related through a wire

Answer 19

They are directly proportional

Question 20

What does the graph relating voltage and current through a wire look like

Answer 20

A straight line going through the origin

Question 21

What is a thermistor

Answer 21

A type of resistor that depends on temperature

Question 22

How does heat effect the resistance of a thermistor

Answer 22

Hot = low resistance
Cold = high resistance

Question 23

What is the symbol of a thermistor

Answer 23

a normal resistor symbol with a straight line underneath it and then going through the resistor

Question 24

What does a thermistor graph look like

Answer 24

temperature on the x axis
resistance on the y axis
and the line looks a bit like the letter ‘c’

Question 25

What does LDR stand for

Answer 25

Light dependent resistor

Question 26

What is a LDR made of

Answer 26

silicon

Question 27

What does a LDR depend on

Answer 27

Light intensity

Question 28

How does light intensity effect the resistance

Answer 28

Bright light - low resistance dark light - high resistance

Question 29

When are LDR's used

Answer 29

street lights

Question 30

What does the graph look for LDR's

Answer 30

light intensity x axis resistance y axis line looks like a c

Question 31

What is a diode

Answer 31

A diode only allows current to flow through it in one direction

Question 32

What way does a diode have to face for current to flow

Answer 32

Forward-biased

Question 33

What is it called when the diode doesn't let current flow

Answer 33

Reversed-biased

Question 34

When the diode is reversed-biased what is the resistance like

Answer 34

Very high so the current doesn't flow

Question 35

What is a variable resistor

Answer 35

A resistor that has an adjustable resistance

Question 36

Does a light bulb follow ohms law

Answer 36

No it is non-ohmir

Question 37

How does the temperature of the filament of a light bulb effect the resistance

Answer 37

As the temperature increase so does the resistance

Question 38

What is power

Answer 38

Power is the rate at which work is done or the rate at which energy is transferred

Question 39

What is equation for power linking energy time and power

Answer 39

P=E/t

Question 40

What is equation for power linking power, voltage and current

Answer 40

P=VI

Question 41

What is equation for power linking power, current and resistance

Answer 41

p=I2R

Question 42

What is equation for power linking power resistance and voltage

Answer 42

P=V2/R

Question 43

What is direct current

Answer 43

Current flows in one direction ONLY

Question 44

What is alternating current

Answer 44

Current is CONTINUOUSLY changing direction

Question 45

What type of current does mains electricity use

Answer 45

alternating current

Question 46

What are the 3 types of wire in mains electricity

Answer 46

Live, neutral, earth

Question 47

What colour is each wire

Answer 47

live- brown neutral - blown Earth - green and yellow

Question 48

What wires does the current normally flow through

Answer 48

neutral and live

Question 49

What is the point of the earth wire

Answer 49

for safety

Question 50

What does the earth wire provide

Answer 50

a low resistance route to the ground

Question 51

What is the point of a fuse

Answer 51

to melt and break a circuit when the current passing through is too high and to ISOLATE the appliance from the mains

Question 52

What does RCD stand for

Answer 52

Residual current device

Question 53

What is a RCD

Answer 53

It detects the difference between the current in the live and neutral wires

Question 54

What does it mean if there is a difference between the current flowing in the live and neutral wires

Answer 54

there is a fault and the current is flowing through some other part of the appliance

Question 55

What will a RCD do if it detects a difference between the live and neutral wire

Answer 55

break (stop the circuit)

Question 56

Which does a fuse or a circuit breaker act faster

Answer 56

circuit breaker

Question 57

What is the current like in a series circuit

Answer 57

the same all the way round

Question 58

What is the current like in a parallel circuit

Answer 58

main current splits and goes through both branches

Question 59

What is the voltage like in a series circuit

Answer 59

The bulbs share the voltage

Question 60

What is the voltage like in a parallel circuit

Answer 60

each bulb gets the full voltage

Question 61

In a parallel circuit if one branch had two bulbs and the other had one which branch would have the higher current

Answer 61

The branch with only one bulb

Question 62

Why does the resistance of the bulb filament increase with the temperature

Answer 62

The atoms in the filament vibrate more vigorously as the temperature increases and electrons have more collisions as they flow through

Question 63

What does the graph look like for the increase of resistance with temperature for the filament of a light bulb

Answer 63

I is on the x axis V is on the y axis The line is a curve shape that looks like the shape of a smiley face