Topic P1-Energy Flashcards
(24 cards)
What is the equation to work out the kinetic energy of an object?
Ek(J)=0.5Xm(kg) X speed2(m/s)
What is the equation for gravitational potential energy?
Ep=mass(kg) x gravitational field strength(kg) x height(m)
What is the equation that links efficiency, useful power output and total power input?
Efficiency = useful power output(W)/total power input(W)
What is the equation that links spring constant, elastic potential energy and extension?
Elastic potential energy(J)= 1/2 x spring constant(N/m) x extension(m)^2
What is the specific heat capacity of a substance?
The amount of energy required to raise the temperature of 1kg of the substance by 1C.
What is the equation that links change in temperature, specific heat capacity, mass and change in thermal energy?
Change in thermal energy(J) = Mass(kg) x specific heat capacity(J/kg) x change in temperature
What two equations can be used to calculate power?
Power(W) = energy transferred(J) / time(s)
Power(W) = work done(J) / Time(s)
What is conduction?
When an object is heated, energy is transferred to the kinetic energy stores of its particles.
This causes the particles to vibrate more, and to collide with each other. During these collisions, energy is transferred between the particles kinetic energy stores.
Do materials with a high thermal conductivity transfer energy between their particles at a faster rate or a slower rate?
Faster rate
What is convection?
Because liquids and gases can flow, the warmer and less dense region will rise above denser, cooler regions. So energetic particles move away from hotter to cooler regions.
What are a few things you can do to prevent energy losses through heating?
Have thick walls that are made from a material with a low thermal conductivity. This means the rate of energy transfer will be slower.
Use thermal installations e.g. double glazed windows and loft insulation.
How can you improve the efficiency of energy transfers?
Insulating objects.
Lubricating them.
Making them more streamlined.
What is the equation that includes efficiency, useful output energy transfer, and total input energy transfer?
Efficiency = useful output energy transfer / total input energy transfer
What is an example of something that uses renewable energy resources?
Vehicles that run on pure biofuels.
What are three examples of non renewable energy resources that we use to heat our homes?
Natural gas is used to heat water, which is then pumped into radiators throughout the home.
Coal is commonly burnt in fireplaces.
Electric heaters which use electricity generated from non-renewable energy resources.
What are three examples of renewable energy resources that we use to heat our homes?
A geothermal heat pump uses geothermal energy resources to heat buildings.
Solar water heaters work by using the Sun to heat water.
Burning biofuel, or using electricity generated from renewable resources.
What is one advantage and disadvantage of wind power?
Advantage – no permanent damage.
Disadvantage – 1500 win turbines are needed to replace one coal-fired power station.
What is an advantage and disadvantage of solar cells?
Advantage – there is no pollution.
Disadvantage – they generate electricity on a relatively small scale.
What is an advantage and disadvantage of geothermal power?
Advantage – reliable
Disadvantage – the cost of building a power plant is often high, compared to the amount of energy it produces.
What is an advantage and disadvantage of hydro-electric?
Adv- can provide an immediate response to an increased demand for electricity
Dis- there is a big impact on the environment due to the flooding of the valley and possible loss of habitat
What is an advantage and disadvantage of wave power?
Adv- no pollution
Dis- disturbing the seabed and the habitats of marine animals
What is an advantage and disadvantage of tidal barrages?
Adv- no pollution
Dis- spoiling the view
What are bio-fuels?
Renewable energy resources created from either plant products, or animal dung. They can be solid, liquid or gas and can be burnt to produce electricity or run cars in the same way as fossil fuels.
What are the 4 steps to investigate specific heat capacity?
1) Measure the mass of the block material, then wrap it in an insulating layer to reduce the energy transferred from the block to the surroundings. Insert the thermometer with a drop of water and heater.
2) Measure the initial temperature of the block and set the potential difference to be 10v. Turn on the power supply and start a stop watch.
3) Take readings of the temperature and current every minute for 10 minutes. Calculate the power supplied to the heater, using P= VI or how much energy has been transferred to the heater, using E=Pt.
4) plot a graph and repeat this experiment with different materials
