Energy

Question 1

What are the 8 energy stores?

Answer 1

Chemical energy
Elastic potential energy
Gravitational potential energy
Magnetic energy
Electrostatic energy 
Nuclear Energy 
Thermal energy 
Kinetic energy

Question 2

What energy transfer occurs when a ball falls?

Answer 2

gravitational potential to kinetic

Question 3

What is the equation used for finding the energy in an objects kinetic energy store?

Answer 3

Ek = 0.5 x m x v^2

kinetic energy = half x mass x volume squared

Question 4

What is the equation used for finding the energy in an objects gravitational potential energy store?

Answer 4

Ep = mgh

Gravitational potential energy = mass x gravitational field strength x height

Question 5

what is gravitational field strength measured in?

Answer 5

N/kg (Newtons per kilogram)

Question 6

What is the definition of specific heat capacity?

Answer 6

How much energy is needed to increase the heat of 1kg of material by 1 degrees

Question 7

What is the equation used to find the energy in an elastic potential energy store?

Answer 7

Ee = 0.5 x k x e^2

Elastic potential energy = half x spring constant x extension squared

Question 8

What is springs constant measured in?

Answer 8

N/m (Newtons per meter)

Question 9

What equation links energy transferred to specific heat capacity?

Answer 9

△E = mc△0

Change in thermal energy = mass x specific heat capacity x temperature change

Question 10

What is conduction

Answer 10

Conduction is when particles vibrate more and collide with each other due to an object being heated and energy transferred to its kinetic energy stores of its particles. During these collisions energy is transferred between particles’ kinetic energy stores

Question 11

Name three ways you can prevent energy losses through heating

Answer 11

1. Have thick walls made from material with a low thermal conductivity
2. Double-glazed windows
3. Loft insulation

Question 12

How does cavity wall insulation reduce the amount of energy transferred out of a house

Answer 12

Cavity walls are made up of an inner and an outer wall with a gap in the middle. The air gap reduces the amount of energy transferred by conduction through the walls.

Question 13

What are the two ways of calculating effciency for an energy transfer?

Answer 13

effciency = useful output energy transfer ÷ total input energy transfer
or
efficiency = useful power output ÷ total power input

Question 14

What is the difference between renewable and non-renewable energy?

Answer 14

Renewable energy is energy that will never run out eg. Solar and wind power and non-renewable energy is energy that will eventually run out eg. coal and natural gas

Question 15

Name the 8 renewable energy sources

Answer 15

1. Wind
2. Solar
3. Geothermal
4. Hydro Electric
5. Wave
6. Tidal
7. Nuclear
8. Biofuel

Question 16

Explain wind power

Answer 16

• Wind turbines get placed in exposed places
• kinetic energy is transferred from the wind and as the blades rotate, the generator inside the turbine produces electricity
• no permanent environmental damage, no fuel costs, minimal running costs
• view and noise pollution, impossible to increase supply, rely on the weather

Question 17

Explain solar cells

Answer 17

• Solar cells generate electric currents directly from sunlight
• no pollution, very reliable in sunny countries, cost-effective, very low running costs
• can’t increase the power output

Question 18

Explain geothermal power

Answer 18

• The slow decay of various radioactive elements eg Uranium inside the Earth
• free energy, reliable, very little damage to the environment, can generate electrivity or heat buildings directly
• aren’t many suitable locations for power plants, high cost for building power plant

Question 19

Explain Hydro-electric power

Answer 19

• The flooding of a valley (by building a big dam), water is allowed out through turbines
• no pollution, can provide an immediate response to increased demand for elc, no fuel costs, minimal running costs, useful for small scale
• big environmental impacts (flooding = rotting vegetation = methane and co2), ugly when they dry up, high initial costs

Question 20

Explain wave power

Answer 20

• Lots o small wave-powered turbines around the coast, moving turbines connected to a generator
• no pollution, no fuel costs, minimal running costs
• disturbs seabed and habitats of marine animals, hazard to boats, fairly unreliable (waves die out when wind drops), high initial costs

Question 21

Explain Tidal Barrages

Answer 21

• big dams across river estuaries with turbines in them
• the tide comes in and fills the estuary, water is allowed out through turbines
• no pollution, pretty reliable, no fuel costs, minimal running costs, generate a significant amount of energy
• prevents free access by boats, alters habitat of wildlife, ugly, height of tide varies, high initial costs

Question 22

Explain bio-fuels

Answer 22

• created from either animal dung or plants proucts
• fairly reliable, supposedly carbon nuetral
• can’t respond to immediate energy demands, very expensive, some areas have had large areas of forest cleared for bio-fuels to be grown, resulted in species loosing their ntural habitats and increases methane nd o2 emissions