Physics Paper One Flashcards
What are the different energy stores?
- Thermal
- Kinetic
- Gravitational Potential
- Elastic Potential
- Chemical
- Magnetic
- Electrostatic
- Nuclear
What is meant by energy lost from the g.p.e store?
What is meant by energy lost from the g.p.e store = Energy gained in the kinetic energy store.
Kinetic energy?
1/2 x Mass x Velocity²
Gravitational potential energy?
Mass x field strength x height
Elastic potential energy?
1/2 x spring constant x extension²
What is meant by specific heat capacity?
The amount of energy needed to raise the temperature of 1kg os substance by 1 degree.
Change in thermal energy?
Mass x specific heat capacity x temperature change
What does the conservation of energy principle state?
Energy can only be transferred, stored or dissipated but can never be destroyed or created.
What are the 2 ways of calculating power?
Energy ÷ Time
Work Done ÷ Time
What is conduction?
The process where vibrating particles transfer energy to neighbouring particles.
What is convection?
Where energetic particles move away from hotter to cooler regions.
How do you reduce unwanted energy transfers?
- Lubrication
- Insulation
What are the 2 ways of calculating efficiency?
Useful output energy transfer ÷ Total input energy transfer
Useful power output ÷ Total power input
What are some examples of non-renewable energy resources?
- Coal
- Oil
- Natural Gas
What are some renewable energy resources?
- The sun (solar)
- Wind
- Water waves
- Hydro-electricity
- Bio-fuel
- Tides
- Geothermal
How is wind power made? Advantages and disadvantages?
Each turbine has a generator in it, therefore the wind rotates it and produces the electricity. There's little pollution made (only when they are being built). \+ Renewable \+ No greenhouse gases produced - Noisy - Ugly - Initial costs are high
What is geothermal power? Advantages and disadvantages?
Produces energy from underground thermal energy stores. It is only possible in volcanic areas where hot rocks lie near to the surface. \+ Essentially free energy \+ Renewable - Expensive - Few suitable locations.
What is bio-fuels?
Renewable energy resources from plants or animal dung. These can be burnt to produce electricity. \+ Carbon neutral \+ Reliable - Costs are high - No space of water for other crops - Areas have been cleared for bio-fuels.
What is current?
The flow of electric charge.
What does a greater resistance mean?
The higher the resistance, the smaller the current that flows through (for a potential difference across the component)
How do calculate charge?
Current x Time
How do calculate potential difference?
Current x Resistance
What are ohmic conductors?
The resistance doesn’t change with current. At a constant temperature, the current flowing through an ohmic conductor is directly proportional to the potential difference across it.
What does ‘I-V Characteristics’ mean?
A graph which shows how the current flowing through a component changes as the potential difference across it is increased. Linear have a straight line.
What is current like in a series circuit?
The current is the same everywhere. i1 = i2
What is resistance in a series circuit?
It adds up R1+R2 = R total