Electric circuits

Question 1

Explain how an electric current flows around a circuit

Answer 1

1. An electric current is a flow of charge
2. It can only flow if the circuit is complete
3. The moving charges are electrons which are negatively charged
4. The current in a circuit is always the same it is never used up

Question 2

What is another name for voltage?

Answer 2

potential difference

Question 3

What is another name for potential difference

Answer 3

voltage

Question 4

Describe the job of a battery in a circuit?

Answer 4

The battery provides the voltage in the circuit which pushes the electrons around making a current flow

Question 5

Combining batteries does what to the voltage in a circuit?

Answer 5

The voltages are combined
eg 2 x 12V batteries gives a voltage of 24V

Question 6

What units are used for voltage

Answer 6

Volts (V)

Question 7

Describe resistance in a circuit

Answer 7

Resistance is anything which slows down the flow of current

Question 8

What is a component in a circuit

Answer 8

Anything you put into it
eg a lamp

Question 9

How does the number of components in a circuit affect the current?

Answer 9

The more components the higher the resistance and the slower the current

Question 10

Will a good conductor of electricity have high or low resistance?

Answer 10

The better the conductor the lower the resistance.

Question 11

What type of energy does a battery contain?

Answer 11

Chemical energy

Question 12

Describe how batteries transfer energy to other components

Answer 12

1. The chemical energy in the battery is transformed into electrical energy
2. The electrical energy is transferred to the components
3. The component, such as bulbs transform the electrical energy into other forms such as light and heat

Question 13

Explain why an ammeter may be connected to a circuit

Answer 13

1. An ammeter measures the current flowing through a circuit in amps (A)
2. You put an ammeter into a circuit in line with the other components, it doesnt need it’s own loop
3. The current through the ammeter is the same as the other components in the circuit such as a bulb.

Question 14

Explain why an voltmeter may be connected to a circuit

Answer 14

1. A voltmeter measures voltage in Volts (V)
   You put a voltmeter into it’s own loop below the component you want to know the voltage of eg a bulb

Question 15

State the component

Answer 15

Electromagnet

Question 16

State the component

Answer 16

Reed switch

Question 17

State the component

Answer 17

simple on off switch

Question 18

State the component

Answer 18

Ammeter

Question 19

State the component

Answer 19

Variable resistor

Question 20

State the component

Answer 20

Resistor

Question 21

State the component

Answer 21

Battery

Question 22

State the component

Answer 22

Push button switch

Question 23

State the component

Answer 23

LED- light emitting diode

Question 24

State the component

Answer 24

Lamp

Question 25

State the component

Answer 25

Light dependent resistor

Question 26

State the component

Answer 26

Semi conductor diode

Question 27

State the component

Answer 27

Junction of conductors

Question 28

State the component

Answer 28

fuse

Question 29

What is the role of the component?

Answer 29

Breaks the circuit if the current is too high

Question 30

What is the role of the component?

Answer 30

reduces current flowing through the circuit

Question 31

What is the role of the component?

Answer 31

switch controlled by a magnetic field

Question 32

State the component

Answer 32

Relay

Question 33

State the component

Answer 33

Terminals

Question 34

State the component

Answer 34

Buzzer

Question 35

What is the role of the component?

Answer 35

switch controlled by an electromagnet

Question 36

What is the role of the component?

Answer 36

Coil of wire with magnetic field

Question 37

What is the role of the component?

Answer 37

only lets the current flow in one direction

Question 38

What is the role of the component?

Answer 38

Resistance decreases when light is shone onto it

Question 39

What is the role of the component?

Answer 39

Lights up when current it passed through

Question 40

What is the difference between series and parallel circuits?

Answer 40

In series circuits the electricity can only flow one way whereas in parallel circuits it can take different routes

Question 41

What are the characteristics of a series circuit

Answer 41

1. The current is the same everywhere on the circuit 2. The voltages across the components add up to make the voltage of the battery or cell 3. The current only takes one route through all of the components

Question 42

What are the characteristics of a parallel circuit?

Answer 42

The current has a choice of different routes The current splits between each of the routes The voltage across each bulb is the same

Question 43

What type of circuit is this?

Answer 43

Series circuit

Question 44

Give the equation for the voltages on this series circuit

Answer 44

Vs = V1 + V2

Question 45

What will the ammeters show about the current on this series circuit?

Answer 45

I = I1 = I2 They will all read the same

Question 46

What type of circuit is this?

Answer 46

Parallel

Question 47

Which ammeter values will be the same?

Answer 47

A1 and A5

Question 48

What is the relationship between A1 and A2,3 and 4

Answer 48

A1 = A2 + A3 + A4

Question 49

This is a picture of an AND circuit Explain what needs to happen to light the bulb

Answer 49

Switch 1 AND switch 2 both need to be closed to complete the circuit

Question 50

This is a gif of a parallel OR circuit Explain what needs to happen to light the bulb

Answer 50

Switch 1 OR switch 2 need to be closed to complete the circuit