P1 Physics Flashcards
Infrared radiation
A type of electromagnetic radiation involving waves instead of particles. This means that radiation can travel through vacuum in space. Like the sun, it is far but we can still feel the heat.
3 heat transfers?
Convection, conduction and radiation
Conduction
Conduction is the movement of heat through a metal/substance
Convection
Heat movement in liquids and gases
Explain convection in fluids
Fluids expand when heated because the particles move faster when they’re cooler. As a result the particles take up more volume
Condensation
Turning gas into liquid
Eg steam
The gas particles keeps themselves together to form bonds and energy is released when this happens
What is the Doppler effect?
When there is an apparent change in frequency and wavelength due to the movement of the source and the observer
Source of sound gets closer to observer?
The wavelength decreases and the frequency increases
Blue shift
Sources is far from observer?
Wavelength increases and frequency decreases
Red shift
If a star is far away from earth this means?
More of its light has been red shifted
What is the microwave in space called?
CMBR - cosmetic microwave background radiation
What is the kinetic theory?
This theory explains different properties in different states of matter
Types of fossil fuels and are they renewable?
Coal, oil and natural gas. They are none renewable
Disadvantages of using fossil fuels
They are non renewable and when they are burnt, they release sulphur dioxide gas, which contributes to acid rain
Coal also releases carbon dioxide Gas which contributes to global warming
What is carbon capture?
Carbon capture is a technology used to prevent carbon dioxide building up into the atmosphere
What are nuclear fuels?
They are nuclear substances used to release heat energy
Advantages and disadvantages of using nuclear fuels?
They don’t release carbon dioxide or sulphur dioxide
But they are non renewable and must be stored safely
Wind energy
Turbines uses wind power to generate electricity
Advantages and disadvantages of wind turbine?
They are renewable
But they spoil landscape view and if there is no wind there is no electricity
Wave, tides and hydroelectric power
They all use water movement to generate electricity
Pros and cons of water energy?
They are renewable and do not release harmful gases to the environment
But they destroy habitats of estuary species. The rotting vegetables will release methane which is a greenhouse gas
What is geothermal energy?
Using hot water and steam underground to turn turbines
Geothermal energy - Hot rocks and volcanic areas
Hot rocks-people drill wells into hot rocks and pump cold water that releases steam and hot water where it drives generators and turbines
Volcanic areas- some rocks contain uranium which the decaying of these substances heats up the rocks and some areas, the rocks heats up the waters and hot water and steam comes up to the surface naturally. The steam can be used turn turbines
Pros and cons of geothermal energy?
It’s renewable and doesn’t release harmful gases into the atmosphere
But most parts of the world do not have hot rocks and volcanic areas that can be exploited
Solar cells
They are devices that convert sunlight into electrical energy
Differences between solar panels and cells?
Panels heat up water systems
Cells convert sunlight into electrical energy
Pros and cons of solar cells?
They are renewable and do not release any harmful gases into the atmosphere
But they are expensive and inefficient. So their cost is quit high. They also do not work at night
Which power stations take longer time to startup?
Nuclear power stations take a long time to start up. Gas fired stations take less time to start up
The national grid- the higher the current, the higher the?
The higher the current, more heat is lost.
To lower these currents the national grid transmits electricity at a lower current, which costs high voltage.
What is the transformer?
Transformer is a device that changes the voltage of an (ac) supply
2 types of transformers?
A transformer that increases voltage is called a step up transformer
A transformer that decreases voltage is called a step down transformer
Law of conservation of energy
Energy can be stored or transferred and cannot be created or destroyed
How do lights travel?
It travels through waves
How can waves be described by?
By their amplitude, frequency and wavelength
How can the speed of a wave be calculated from?
From its frequency and wavelength
What are waves?
Oscillations that travel from one place to another
What do waves travel through?
They travel through the median (solid,liquid or gas)
What types of waves that don’t travel through the median?
Infrared and electromagnetic radiation
What are transverse waves? Examples?
oscillations traveling perpendicular to the direction of energy transfer
Light and electromagnetic waves
What are longitudinal waves?
Oscillations are parallel to the direction of energy transfer
Sound waves
Describe diffraction
When a wave goes through a small gap, it will spread out. The spread will depend on the size of the gap
Describe refraction
When sound waves goes through a boundary, it will cause them to change direction
Law of reflection?
Angle of incidence is equal to the angle of reflection
What do diffraction of waves allow?
It allows low frequency waves to be received behind hills
What is frequency?
The number of cycles passing a point in one second
What is the amplitude?
The height of the crest
What’s an oscillation?
A repeated pattern of movement
What are power station?
Power stations that control electricity around the whole country
