National Grid/ Static electricity

Question 1

What is the national grid?

Answer 1

a giant system of cables and transformers linking power stations to homes and businesses

Question 2

What do the Power stations in the National Grid do?

Answer 2

throughout the day, electricity usage (demand) changes. Power stations have to produce enough electricity for everyone to have when they need it

They transfer the energy supply into electrical energy

Question 3

Explain why a smaller number of large power station is more efficient than building many small local power stations.

Answer 3

because large stations can be more efficient.

this is because most power plants use steam turbines which are more efficient at high steam temperatures and the bigger the plant, the bigger the boils, so the higher the steam temperature.

Question 4

What do step-up transformers do?

Answer 4

transformers that increase the potential difference from the power station to the transmission cables

This reduces the amount of current and therefore also reduces the heating effect caused by current flowing in the transmission cables

Question 5

Reducing the heating effect …

how does it affect the transmission

Answer 5

reduces energy loss so makes the transmission more efficient.

Question 6

What do transmission cables do?

Answer 6

they transfer the electricity

Question 7

What do Step down transformers do?

Answer 7

reduce the potential difference from the transmission cables to a much lower value of domestic use

Question 8

How do you make material electrically charged?

Answer 8

by rubbing two insulating materials against each other

Question 9

What does the friction between the two insulating material result in? (in terms of electrons)

Answer 9

moves negatively charged electrons from one material to another

Question 10

Why does charge remain on the object (after rubbing two insulating materials together)

Answer 10

because the materials are insulators

Question 11

Why can’t charge remain on a conductor?

Answer 11

because they conduct the charge to earth so it cannot build up

Question 12

What is an isolated object?

Answer 12

an object that has no conducting path to earth

Question 13

How are electrical sparks formed?

Answer 13

As the charge on an isolated object increases the potential difference between the object and Earth increases

When the potential difference become high enough a spark may jump across the gap, from the object to any earthed conductor near to it

Question 14

why could electric sparks be dangerous?

Answer 14

because they could serve as a source of ignition

Question 15

what type of force is an electrostatic force

Answer 15

a non- contact force

Question 16

when both objects carry the same charge they…

Answer 16

repel

Question 17

when the objects carry opposite charges they will

Answer 17

attract

Question 18

what type of field does a charged object create around itself?

Answer 18

an electric field

Question 19

The strength of the electric field at any point depends on what two factors?

Answer 19

• the distance from the object (closer = stronger)

- the amount of charge (higher =stronger)

Question 20

in field diagrams what do lines close together indicate?

Answer 20

that the field is strong and there’s a greater chance a spark will occur