energy

Question 1

What is the advantage of transmitting electricity at a very high potential difference?

Answer 1

less thermal energy is transferred to the surroundings

Question 2

Define the specific heat capacity of a substance

Answer 2

The amount of energy needed to raise the temperature of 1 kg of a substance by 1°C

Question 3

State the units for specific heat capacity

Answer 3

j/degrees Celsius/kg

Question 4

what is the definition of power?

Answer 4

The rate of which energy is transferred

Question 5

Describe the energy changes involved when a ball is thrown upwards and then returns to it starting position

Answer 5

upwards:KE is converted to GOE
peak:maximum GPE,zero KE
downwards:GPE is converted to KE

Question 6

explain why a bungee jumper slows down once the cord begins to stretch

Answer 6

Kinetic energy decreases since it is converted to a elastic potential

Since kinetic energy is proportional to velocity squared as kinetic energy decreases, so does velocity

Question 7

give two examples of chemical energy stores

Answer 7

Food fuel batteries

Question 8

State for different stores of energy

Answer 8

Kinetic energy, gravitation and potential energy, elastic potential energy, chemical energy

Question 9

State any changes in the total energy of a bar that is kicked, assuming that no external forces act

Answer 9

The total energy of the system remains constant due to the conservation of energy

Question 10

what is waste energy?

Answer 10

The energy that is not used by the device for its desired purpose

Question 11

How can the efficiency of a system be increased?

Answer 11

reducing waste output(by lubrication, thermal insulation)

Recycling waste output (recycling thermal waste energy as an input energy)

Question 12

State the consequence for energy transfer of material with a high thermal conductivity

Answer 12

The rate of energy transfer for the material is higher than material with a lower thermal conductivity

Question 13

Do double glaze windows have a higher or lower firm or conductivity than single glaze windows?

Answer 13

Low, meaning less energy transfers through them

Question 14

What key factors affect the rate of cooling of a building?

Answer 14

The thickness of the walls, the thermal conductivity of the walls

Question 15

How can the efficiency of a mechanical machine with moving parts be improved?

Answer 15

lubricate any moving parts to reduce the friction and therefore energy loss due to heating

Question 16

how can the efficiency of a radiator be improved?

Answer 16

Installing metal foil sheets behind the radiator to reflect the heat back into the room rather than it being absorbed into the walls

Question 17

How can the efficiency of boiling water in a pan being improved?

Answer 17

By placing a lid on the pan to reduce the heat loss from the top

Question 18

what is a renewable energy resource?

Answer 18

An energy source, which can be a replenished as it is been used up

Question 19

Give four examples of renewable energy resources

Answer 19

Wind, hydroelectricity, tidal ,solar

Question 20

what are the advantages of generating power using gas rather than coal?

Answer 20

Flexible generation: gas power stations have short start-up time so it can be switched on/off more readily

Lower missions of carbon dioxide

Question 21

State two disadvantages of using renewable energy resources to generate power

Answer 21

Output often determined by external factors(like wind speed) so supply is uncertain

Generating power through other means is often more efficient and economical beneficial

Question 22

Explain environmental impacts of burning fossil fuels

Answer 22

carbon dioxide contributes the greenhouse effect and causes global warming

Sulphur dioxide leaves to acid rain which can damage buildings and crops

Question 23

State three advantages of fossil fuels as energy resource

Answer 23

reliable: not dependent on external factors who can generate power any time

Can produce larger amount of energy for a given quantity

Still relatively abundant, so cost-effective

Question 24

State three advantages of nuclear power

Answer 24

Very large amounts of energy for relatively small quantities of fuel

Doesn’t release greenhouse gases and so doesn’t contribute to climate change

Low fuel costs

Question 25

State three disadvantages of nuclear power

Answer 25

produces nuclear waves which is a harmful to humans and must be safely stored for centuries

Nonrenewable energy source

Risk of nuclear accidents, which have fatal consequences on humans and the environment

Question 26

How does hydroelectric power produce energy?

Answer 26

rain water collects behind a dam when this water is released, it is used to turn a turbine
this turnbine turns a generator which produces electricity

Question 27

what are some disadvantages of using biofuels?

Answer 27

When plants are burned or decay, they release carbon

in order to grow biofuels, you need to destroy land which leads to problems because:
The land could’ve been natural habitats
destroy land may involve burning plants growing on it which could release carbon dioxide

Growing biofuels reduce the land available for growing food

Question 28

what are the advantages of tidal energies sources?

Answer 28

they do not produce greenhouse gases
They’re quite reliable, as tides happened twice a day
They’re cheap to run as tides are natural and so are free

Question 29

what are the disadvantages of hydroelectric power?

Answer 29

The dam may cause flooding
It can cost a lot to install the required infrastructure

Question 30

What are some advantages of solar panels?

Answer 30

they don’t cause harm to the environment
There are renewable resource
They can be used in remote areas where the other types of energy are less accessible

Question 31

Give an example of a social factor which may act as a deterrent for certain types of energy production

Answer 31

Visual pollution
Sound pollution

Both of these are disadvantages of wind farms