P3

Question 1

What is the greenhouse effect?

Answer 1

-some radiation frequencies pass through the ozone layer
-heat up earth earth absorbs radiation
-emits it in evening
-radiation blocked from leaving earth by greenhouse gases(methane,water vapour,carbon dioxide)
Warms earth up more

Question 2

What is carbon dioxide?

Answer 2

Greenhouse gas

Over last 200 years co2 increase correlates with temperature increase

Question 3

What is the effect of global warming?

Answer 3

temperature causes glaciers to melt

• sea levels rise
• floods
• extreme weather due to evaporating water
• increased convection in the atmosphere, greater wind speeds

Question 4

What is the power formulae

Answer 4

Energy transferred(joules)= power(watts)•time(seconds)

Energy transferred(KWh)= power(KW)•time(hours)

Electrical power(watts)=current(A)•voltage(V)

Appliance current(A)= Appliance power(w) divided by supply voltage (v)

Question 5

What is current in a circuit?

Answer 5

• a component that transfers electrical energy into useful forms
• current in connecting wires wastefully transfers electrical energy to heat

Question 6

What is the formula for cost of electricity?

Answer 6

Electricity(units)=power(KW)•time(hours)

Cost of electricity=units•cost per unit

Question 7

What is a sankey diagram?

Answer 7

thickness of arrow=amount of energy

Question 8

What is the formula for energy efficiency?

Answer 8

Efficiency=energy usefully transferred divided by total energy transferred

Question 9

How can we save electricity?

Answer 9

Personal
Use A rated appliances
Turning off components 
National
Use transport effiency
Better insulation in houses
More efficient power stations

Question 10

How do generators work?

Answer 10

A magnet turns inside a role of copper, wire the magnetic field changes as the magnet rotates

Question 11

Why is the voltage higher when being transported?

Answer 11

More efficient, as less electricity is wasted, because the current is lower

Question 12

What are the advantages and disadvantages of nuclear power?

Answer 12

Ad.
Produces large amounts of electricity
Cheaper than coal and gas
No greenhouse gases
Reliable
Efficient needs little fuel
Dis.
Nuclear waste
Stations are expensive to decommission 
Not renewable

Question 13

What are the advantages and disadvantages solar energy?

Answer 13

Ad.
Renewable
No CO2
Cheap when running
Long lasting
Dis.
Relies on sun
Expensive
Inconsistent 
Inefficient

Question 14

What are the advantages and disadvantages wind?

Answer 14

Renewable
No CO2
Can be built on land and see
Long lasting
Dis.
Large amount of land needed
Needs wind
Expensive to set up
Produces low frequency noise
Inefficient

Question 15

What are the advantages and disadvantages of fossil fuels?

Answer 15

Ad.
Reliable
Known technology
Cheaper than renewables
Quite efficient
Dis.
Produces CO2
Not renewables 
Have to rely on other countries

Question 16

What are the advantages and disadvantages biofuel?

Answer 16

Ad.
Renewable
Inexhaustible
Medium power output
Carbon neutral
Dis
Needs large amounts of land to be produced
Expensive to produce
Produces CO2
Trees grow slowly
Inefficient

Question 17

What are the advantages and disadvantages hydroelectric

Answer 17

Ad.
Can provide large amounts of electricity
Can be turned on and off quickly
Can pump water back behind the dam to store energy
Dis.
Can flood areas
Rotting plants in the water produce methane gas
Cost a lot to build

Question 18

What are the primary energy sources and a secondary source?

Answer 18

Primary
-coal,gas oil-fossil fuels
-nuclear fuel
-renewable sources
Secondary
-electricity