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69 Cards in this Set
- Front
- Back
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List the 4 energy stores |
Chemical energy store Gravitational potential energy store Elastic potential energy store Thermal energy store |
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How can energy be transferred |
By heating, by waves, by an electric current, by a force when it moves an object |
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Energy cannot be... |
Created or destroyed |
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Equation for work done |
W=fd |
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Gravitational potential energy is increased when it moves |
Up |
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Gravitational potential energy equation |
Ep=mgh |
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Kinetic energy equation |
Ek=0.5mv^2 |
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Elastic potential energy equation |
Ee=0.5ke^2 |
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As energy dissipates it gets |
Less and less useful |
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What useful and wasted energy does a TV use |
Useful light energy and sound energy Wasted heat energy |
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Equation for efficiency |
Efficiency=useful/total *100 |
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What can help increase efficiency of machines? |
Lubrication to reduce heat energy by friction |
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What energy is useful and wasted by a hairdryer |
Kinetic energy, heat energy are useful Sound energy is wasted and heat energy wasted by heating the case too |
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Power equations |
P=w/t P=VI P=E/t P=I^2r |
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What material conducts best |
Metal |
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What materials insulates best |
Wool and fibre glass |
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The higher the thermal conductivity of a material |
The higher the rate of energy transfer through it. |
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What depends on how much infrared radiation an object emits? |
It’s temperature, the hotter it is the more infrared radiation |
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What is black body radiation? |
Radiation admitted by a body that absorbs all the radiation incident on it. |
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What increases if it absorbs more radiation than it emits |
The temperature of the object |
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What is an objects specific heat capacity? |
The amount of energy needed to change the temperature of 1kg of the substance by 1 degree |
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What is the equation for specific heat capacity |
Energy=mass x specific heat capacity x temp change. |
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Give examples of how energy transfer from houses can be reduced |
Loft insulation Cavity wall insulation Double glazed windows Aluminium foil behind radiators |
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What is a cavity wall |
Brick, insulation, brick |
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How do hydroelectric power stations work |
Generators are turned by the gravitational potential energy of the downhill water. |
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How do solar panels work? |
Use the suns energy to heat water directly |
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What is a downside to renewable energy |
They are expensive to install and can cause noise pollution and people object as the views can be ruined. |
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Insulating materials that become ... charged when rubbed ... electrons. |
Positively , lose Negatively, gain |
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Insulating materials that become ... charged when rubbed ... electrons. |
Positively , lose Negatively, gain |
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What is the equation for the electric current of a circuit |
I=Q/T |
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What is the equation for voltage in a circuit? |
V=E/Q |
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What is the equation for resistance? |
R=V/I |
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What is the equation for resistance? |
R=V/I |
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What is this graph for? |
A resistor |
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What is this graph for? |
A filament lamp |
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What is this graph for? |
A diode |
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A thermistors resistance...if it’s temperature... |
Decreases, increases |
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A thermistors resistance...if it’s temperature... |
Decreases, increases |
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An a LDRs resistance ... if the light intensity on it ... |
Decreases, increases |
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How is alternating current different to direct current? |
DC flows in only one direction, alternating current repeatedly reverses it’s direction of flow. |
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What colour is the live wire |
Brown |
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What colour is the live wire |
Brown |
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What colour is the neutral wire |
Blue |
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What colour is the earth wire? |
Green and yellow |
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What is the equation for energy transferred? |
E=P x t |
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What is the equation for energy transferred? |
E=P x t |
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How do you work out the correct rating for a fuse |
Electrical power(watts)/ potential difference(volts) |
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What is the equation for density |
Density= mass / volume |
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When a substance changes state it’s mass ... because the number of particles ... |
Stay the same |
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When a substance changes state it’s mass ... because the number of particles ... |
Stay the same |
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Increasing the temp of a substance does what to its energy? |
Increases its internal energy |
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What is the equation for specific latent heat |
E=m x L |
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What does specific latent heat mean? |
It is the energy needed to melt (or boil) 1kg of a substance without changing its temperature. |
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Why does the pressure of a gas increase if it’s temp increases? |
The molecules move faster so they hit surfaces with more force and the number of impacts per second increase so the total force of the impacts increases. |
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The relationship between volume and pressure of a gas at a constant temperature is |
Inversely proportional |
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What does a radioactive substance have? |
It contains unstable nuclei that become stable by emitting radiation. |
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What is alpha decay? |
The nucleus loses 2 protons and 2 neutrons and emits them as an alpha particle. |
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What is alpha decay? |
The nucleus loses 2 protons and 2 neutrons and emits them as an alpha particle. |
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What is beta decay? |
A neutron in the nucleus changes into a proton and an electron is created in the nucleus and instantly emitted. |
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Alpha radiation is stopped by |
A thin sheet of paper |
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What is beta radiation stopped by |
Aluminium shed or thin lead |
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What is beta radiation stopped by |
Aluminium shed or thin lead |
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Gamma radiation is stopped by |
Thick lead sheet, 1m thick concrete |
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Radiation is dangerous because |
They ionise substances they pass through, ionisation in a living cell can damage or kill the cell. |
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What is a half life? |
The average time it takes for the number of nuclei of the isotope in a sample to halve. |
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What can radioactive isotopes be used for? |
Medical imaging, treatment of cancer, tracers to monitor organs. |
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What is nuclear fission? |
The splitting of an atoms nucleus into two smaller nuclei and the release of two or three neutrons and energy. |
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What is nuclear fusion |
The process of forcing the nuclei of two atoms close enough together so that they form a single larger nucleus and emit energy. |
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Risks of radiation |
Inside body alpha radiation is very dangerous and affects all surrounding tissue. Outside the body alpha radiation poses some danger as it can damage retinal and skin cells. Beta and gamma radiation are dangerous because they reach cells throughout the body. |
