p3

Question 1

where does the most the energy we use come from

Answer 1

fossil fuels such as oil, coal or gas

Question 2

what is a biofuel

Answer 2

any fuel obtained from living or recently living organisms

Question 3

what are benefits of biofuels

Answer 3

renewable sources of energy
carbon neutral

Question 4

give some examples of biofuels

Answer 4

waste vegetable oil, methane, ethanol

Question 5

what fuel is used in nuclear power stations

Answer 5

uranium or plutonium

Question 6

how is uranium used in a nuclear power station

Answer 6

nucleus of uranium atom is unstable and can split in two which releases energy.
there are lots of uranium nuclei in the reactor core and the energy releases is used to heat water turning into steam

Question 7

what are examples of renewable energy

Answer 7

wind, waves and the tides

Question 8

how do waves produce energy

Answer 8

movement of waves in the sea drive a floating turbine that turns a generator.

Question 9

how does a hydroelectric power station work

Answer 9

water is collected at a reservoir at the top of a hill and when the water flows down the hill it turns turbines.

Question 10

what happens at a hydroelectric power station when demands are low

Answer 10

the same water is pumped from the bottom of the hill to the top to be used again

Question 11

how does a solar cell work

Answer 11

transfers suns electromagnetic energy directly into electrics energy.

Question 12

why are solar cells only used to power small devices

Answer 12

as each cell only produces small amount of energy

Question 13

what can a large number of solar cells create

Answer 13

solar panels

Question 14

what do solar heating panels do

Answer 14

use the suns energy to heat water directly

Question 15

what does a solar power tower do

Answer 15

uses thousands of mirrors to reflect sunlight onto a water tank which heats water and produces steam which then drives turbines

Question 16

what is geothermal energy

Answer 16

comes from energy releases by radioactive substances .

Question 17

how does a geothermal power station work

Answer 17

very deep holes are drilled and cold water is pumped down to the hot rocks and the water Is heated and comes back s steam which drives turbines

Question 18

what are some disadvantages of fossil fuels

Answer 18

non renewable resources
when they are hurt, greenhouse gases are released
burning coal and oil produces sulphur dioxide which causes acid rain

Question 19

what are the advantages of nuclear power

Answer 19

do not produce greenhouse gases
transfers much more energy per kg than fossil fuels

Question 20

what are the disadvantages of nuclear power

Answer 20

used fuel rods contain radioactive waste that must be stored safely for centuries
an accident can make the surrounding area unsafe for years

Question 21

what are some advantages of renewable energy sources

Answer 21

they will not run out
do not produce greenhouse gases

Question 22

what are some disadvantages of renewable energy resources

Answer 22

cant currently meet world demand for energy
wind tidal and hydroelectric can affect plant and animal life and can be eye sore

Question 23

what is base load demand

Answer 23

the constant amount of electricity provided by nuclear and coal fire power stations

Question 24

how is seasonal variable demand met

Answer 24

using gas fired power stations and pumped storage schemes

Question 25

when are renewable energy resources used

Answer 25

when demand is high and the conditions are suitable

Question 26

what power station shave the longest and shortest start up time

Answer 26

nuclear is longest
then coal and oil
natural gas is shortest