electrcity-PAPER 1

Question 1

What is the national grid?

Answer 1

system of cables and transformers linking power stations to homes and business

Question 2

What do power stations do?

Answer 2

transfers energy supply into electrical energy

Question 3

Why is it efficient using a small number of large power stations?

Answer 3

because most power plants use steam turbine which are more efficient at higher steam temperature the bigger the plant the bigger the boiler so higher the steam temp

Question 4

What do step up transformers do?

Answer 4

increase potential difference from power station to transmission cables
reduces the current and the heating effect caused by flowing in the transmission cables

Question 5

What makes the transmission cable efficient?

Answer 5

reduces heating and energy loss

Question 6

What do transmission cables do?

Answer 6

transfer electricity

Question 7

What does step down transformers do?

Answer 7

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

Question 8

What does it mean if there is a high potential difference

Answer 8

Higher potential difference or current will use more energy per second that one with low potential difference or current

Question 9

what is the equation for power?

Answer 9

P=VI

P= I2 R

Question 10

What is in a transformer?

Answer 10

2 coils of wire
primary and secondary
which is wrapped around an iron core
when there is an ac supply in one there is an ac supply in the other

Question 11

How do you increase an energy transfer?

Answer 11

amount of wasted energy needs to be reduced

Question 12

Give an equation for energy transfer

Answer 12

E=pt
energy=lower x time
E=QV
energy transferred=charge flow x potential difference