Electricity

Question 1

What color is the live wire

Answer 1

Brown

Question 2

What color is the neutral wire

Answer 2

Blue

Question 3

What color is the Earth wire

Answer 3

Green and yellow stripes

Question 4

What’s the use of the neutral wire

Answer 4

The neutral wire complete the circuit

Question 5

What’s the use of the live wire

Answer 5

The live wire carries the alternating potential difference from the supply

The live wire is a safety wire to stop the appliances becoming live

Question 6

What is the potential difference between the live wire and the Earth wire

Answer 6

230 V

Question 7

Where is the neutral wire

Answer 7

The neutral wire is close to the Earth

Question 8

What is the use of the Earth wire

Answer 8

The Earth where is a safety wire to stop the appliances become in live

The Earth where is at 0V It only carries a current if there is a fault

Question 9

Means electricity is an AC supply in the United Kingdom has a frequency of what

Answer 9

It has a frequency of 50 Hz and is about 230 V

Question 10

The every day electric Apliances are designed to do what

Answer 10

To bring about energy transfers

Question 11

The amount of energy and appliance transfers depends on what

Answer 11

How long the appliance is switched on for and the power of the appliance

Question 12

How is work done

Answer 12

Work is done when charge flows in a circuit

Question 13

What is the national grid

Answer 13

The national grid is a system of cables and transforms linking power stations to consumers

Question 14

How is that electric power transferred

Answer 14

The electric power is transferred from power stations to consumers using the national grid

Question 15

What are step up transformers used for

Answer 15

Step up transformers are used to increase the potential difference from the power station to the transmission cables

Question 16

What’s the use of step down transformers

Answer 16

Step down transformers are used to decrease to a much lower value the potential difference of the domestic use

Question 17

What is the electric current a flow of

Answer 17

The electric current is a flow of electrical charge

Question 18

What does the current through a component depend on

Answer 18

The resistance (I) of the component and the potential difference (V) across the component

Question 19

The greater the resistance of the component What happens to the current

Answer 19

The greater the resistance of the component the smaller the current for a given potential difference (pd) across the component

Question 20

What happens to the resistance of a thermistor when the temperature increases

Answer 20

The resistance of a thermistor decreases as the temperature increases

Question 21

What happens to the resistance of an LDR when the light intensity increases

Answer 21

The resistance of an LDR decreases as the light intensity increases

Question 22

What is the use of an LDR

Answer 22

It switches lights on when it gets dark 

Question 23

What’s the difference between direct current and alternating current

Answer 23

Direct current (DC): the electric charge (current) only flows in one direction

Alternating current (AC): the electrical charge (current) changes directions

Question 24

Describe the difference between series and parallel circuit

Answer 24

A series circuit is where resistors are connected together in the same line, however in a parallel circuit resistors are connected in parallel.

Question 25

Explain why adding resistors in a series increases the total resistance while adding resistors in parallel decreases the total resistance?

Answer 25

In a parallel circuits the net resistance decreases as more components are at it because there are more paths for the current to pass through. Adding resistors in series always increases the total resistance the current has to pass through each resistor intern so adding an additional resistor adds to the resistance already encountered.

Question 26

Explain the design and use of DC circuits for measurements and testing purposes.

Answer 26

A DC circuit is a direct current that is steady constantly flowing in the same direction in a circuit from positive to negative.

Question 27

Define potential difference

Answer 27

Potential difference is Voltage

Question 28

Describe a parallel circuit

Answer 28

The potential difference across each component is the same or in other words the voltage across each component is the same. The total current of the whole circuit is the sum of the currents through the separate components.

Question 29

What does linear and nonlinear mean

Answer 29

A linear circuits is one who’s parameters are constant with time and they do not change with voltage or current, a nonlinear circuit is that circuit who’s parameters change with voltage or current.

Question 30

What is a series circuit

Answer 30

In a series circuit the same current flows through each component. The total potential difference of the power supply is shared between the components. The total resistance of each component is the sum of all the components.

Question 31

For an electric charge to flow through a closed circuit what must it include

Answer 31

It must include a source of potential difference

Question 32

How do you increase efficiency of intended energy transfer

Answer 32

Thermal insulation lubrication and streamlining

Question 33

Describe the main energy source available

Answer 33

The main energy sources available are fossil fuels such as coal gas and oil nuclear power biofuel wind power hydroelectricity tidal power and solar power and geothermal power and sun and water and sun and water waves.

Question 34

Why are some energy sources more reliable than others

Answer 34

The non-renewable sources are the most reliable as they can be used at any time. However they produce more greenhouse gases.

Question 35

Name some energy sources that are renewable and nonrenewable

Answer 35

Sunlight and wind renewable resources fossil fuels such as coal oil and gas are non-renewable

Question 36

How can you reduce unwanted energy transfers

Answer 36

Thermal insulation lubrication and streamlining

Question 37

Where is energy transferred in a closed system

Answer 37

In a closed system there is no energy added and no energy can escape the total energy in the system remains the same