Electric circuits (topic 10)

Question 1

How are voltmeters arranged in a circuit?

Answer 1

in parallel around a component

Question 2

WHat does the diode symbol look like?

Answer 2

a back skip button in a circle

Question 3

What does a resistor symbol look like?

Answer 3

a rectangle

Question 4

What does a variable resistor symbol look like?

Answer 4

A rectangle with an arrow point diagonally upwards

Question 5

What does a fuse symbol look like?

Answer 5

a rectangle with a line through the middle

Question 6

What is the current?

Answer 6

The rate of electron flow

Question 7

What happens to the current in a series circuit at different point in the circuit?

Answer 7

Stays the same

Question 8

What happens to the current in a parallel circuit when the amp meter is in different places?

Answer 8

Changes as the current is split equally down the different paths.

Question 9

What is potential difference?

Answer 9

A potential difference, also called voltage, across an electrical component is needed to make a current flow through it.

Question 10

What is Vt equal to in a series circuit?

Answer 10

V1 + V2 + V3….

Question 11

What Vt equal to in a parallel circuit?

Answer 11

Vt = V1 = V2 = V3…

Question 12

What is electrical charge measured in?

Answer 12

Coulombs (C)

Question 13

What is the equation which relates charge to current and time?

Answer 13

charge = current x time

Question 14

Why does the current go down when more bulbs are added?

Answer 14

Because they feel more resistance

Question 15

How do you increase the resistance?

Answer 15

Make the wire thinner or longer as the electrons will hit more particles

Question 16

What does the current-voltage graph look like for a fixed resistor?

Answer 16

a straight diagonal line with a positive correlation

Question 17

How do you work out the gradient of a current-voltage graph?

Answer 17

change in y/change in x

Question 18

How do you work out the resistance from a current-voltage graph?

Answer 18

Voltage/current

Question 19

What does the current-voltage graph look like for a filament?

Answer 19

s shape- from one corner to the other

Question 20

What does the current-voltage graph look like for a Diode?

Answer 20

no voltage till a positive voltage and then curves upwards

Question 21

Why is there no current when the voltage is negative in the diode?

Answer 21

because the current only flows one way

Question 22

How does resistance change in a thermistor?

Answer 22

When there is a increased temperature there is less resistance

Question 23

What relates energy to current, time and potential difference?

Answer 23

energy = current x potential difference x time

Question 24

What is ohms law?

Answer 24

potential difference = current times resistance

v = I x R

Question 25

What equation relates energy voltage and charge?

Answer 25

energy= charge x voltage

Question 26

What does the current voltage graph look like for a fixed resister?

Answer 26

a straight diagonal line; as current increases, so does the voltage

Question 27

What is a thermistor?

Answer 27

a component which resistance decreases when temperature increases

Question 28

What is DC voltage?

Answer 28

when current flows constantly from positive to negative

e.g. cells and batteries

Question 29

What is AC voltage?

Answer 29

Mains electricity which produces an alternating current which continually changes direction

Question 30

What does the UK mains oscillate at?

Answer 30

50 Hz

Question 31

What does the earth wire in a plug do?

Answer 31

connects the meal parts of an appliance to the ground

Question 32

How does a fuse act as a safety device?

Answer 32

a Thin wire inside which can hold a maximum charge that the socket can take and will break if the charge exceeds that to stop to much current from flowing round the circuit or it catching fire

Question 33

How do circuit breakers act as a safety device?

Answer 33

detect a change in current and safely switch off the supply if there is too much current

Question 34

What is bad about circuit breakers?

Answer 34

you can still get shocked

Question 35

What is good about circuit breakers?

Answer 35

they can be turned of quickly

-can be switched back on

Question 36

How is lightning made in a storm?

Answer 36

Clouds rub together creating static and friction. a charge is created as electrons are transferred. Lightning is made as elections jump to earth or something like that correct me

Question 37

What causes and electric shock?

Answer 37

when a build up of charge and u touch it and the electrons jump to you because you ore either relatively positive or negative

Question 38

When can static be dangerous?

Answer 38

When refuelling planes because a lot of static builds up when fuel enters the plane so it can spark to the metal on the plane and set the fuel alight.

Question 39

How can static be useful?

Answer 39

In electrostatic sprayers which charge the paint or insectide negative so that they repel from each other and spread out and attract to the object so less is wasted. they get the charge from a electrode in the nozzle.

Question 40

What is energy measured in?

Answer 40

Joules

J

Question 41

What is Power measured in?

Answer 41

Watts

W

Question 42

What is electric charge measured in?

Answer 42

Coulomb

C

Question 43

What is electric potential difference measured in?

Answer 43

Volts

V

Question 44

What is electrical resistance measured in?

Answer 44

Ohm

Ohm sign

Question 45

What is resistance? (definition)

Answer 45

the measure of how difficult it is for electricity to flow.

the resistance the electrons feel as they flow

Question 46

What is the definition of power?

Answer 46

A measure of how quickly energy is transferred.