Physics 1, 2, 3 Questions Flashcards
How are P-waves different to S-waves?
P waves:
- Travel through solids and liquids
- Faster
- Longitudinal
S waves:
- Travel through solids
- Slower
- Transverse
What is the difference between analogue and digital signals?
Analogue can take any value within a certain range. Digital can only take two values, on/off or 1/0.
What does convection happen in?
Liquids and gases
What is Multiplexing?
Lots of different signals can be transmitted down a single optical fibre at the same time, so minimal cables are needed.
Why does convection happen here?
It happens in liquid and gas because the particles are free to move, whereas in solids, particles can’t move.
What is Diffraction?
When waves spread out at the edges as they pass through a gap or past an object.
What is insulation payback time?
It is the time it takes for the money you save annually to cover the cost of the insulation.
What is the specific latent heat for boiling?
The amount of energy needed to boil 1kg of material without changing the temperature.
What Is The Specific Latent Heat Of Melting?
The amount of energy needed to melt 1kg of material without changing its temperature
What is Specific Heat Capacity?
The amount of ENERGY needed to raise the temperature of 1KG of a substance by 1 DEGREE
What is Specific Latent Heat?
The energy needed to CHANGE STATE
How does a star form?
Gravity pulls dust and clouds together to create an interstellar dust cloud. The gravitational energy is converted to heat energy, raising the temperature to create a protostar. This high temperature causes hydrogen nuclei to fuse (thermonuclear fusion) which releases energy in the form if heat and light. This then creates a star.
What are the advantages of a wind turbine?
- Cheap to run
- Doesn’t pollute
- Renewable
Up to what wavelength are radio signals refracted back to Earth?
Up to 300m
What are the disadvantages of a wind turbine?
- Visual/noise pollution
- Wind may not be fast enough
- Expensive to set up
How is a black hole formed?
Stellar nebula, massive star, red supergiant, supernova, black hole
What is Electromagnetic Induction?
The creation of voltage in a wire which is experiencing a change in magnetic field.
What are the advantages of photocells?
- There are no moving parts
- Low maintenance
- Last a long time
- No power cables
- Renewable and doesn’t pollute
What do seat belts do?
Stretch slightly, increasing the time taken for the wearer to stop. This reduces the force acting on the chest
How do ABS brakes work?
Ordinary brakes skid when the driver brakes hard, ABS brakes automatically pump on and off to stop the wheels locking and prevents skidding
What are the disadvantages of Photocells?
- No sunlight = No power
- Not useful in bad weather
What do crumple zones do?
Crumple and change shape on impact, increasing the time taken for the car to stop.
What are ABS brakes?
Anti-lock Braking System helps drivers keep in control of the car steering when braking hard.
What do air bags do?
Increases collision time and slows you down more gradually
How is thinking distance affected?
- how fast you are going
- how dopey you are
What are the disadvantages of using electric cars and solar panels?
They are expensive to make and buy and pollution is created by making them.
How is braking distance affected?
- How fast you are going
- How heavily loaded your car is
- How good your brakes are
- How good the grip is
What different things affects fuel consumption?
Heavy cars, Faster driving, Frequent braking and acceleration, road conditions and tyre quality
To get a bigger voltage, what 3 things should you increase?
- Strength of magnet
- Number of turns on coil
- Speed of movement
What is a step up transformer used for?
To increase the voltage from the generator to the National Grid.
What is a step down transformer used for?
To bring the voltage down to safe usable levels for homes.
What is Off-peak electricity?
Electricity supplied during the night
Why is off peak electricity an advantage?
- It is cost effective
- Cheaper
What are the disadvantages of off peak electricity?
- There can be an increase in fires because no one is watching
How is alpha radiation stopped?
With a sheet of paper
How is beta radiation stopped?
With thin aluminium.
How is gamma radiation stopped?
With a thick block of lead
What are the advantages of nuclear power?
- Can make lots of energy without making a lot of CO2
- Relatively cheap
- Releases more energy than chemical reactions
What are the disadvantages of nuclear power?
- Expensive to build and maintain
- Takes longer to start up
- Processing uranium before you use it causes pollution
- Always a risk of leaks of radioactive material
- Uranium is a non-renewable
What is a meteor?
Rocks or dust that enters the Earth’s atmosphere.
What is a comet?
Balls of rock, dust and ice which orbit the Sun in very elongated ellipses.
What is a NEO?
Asteroids or comets which might be on a collision course
what are the advantages of Unmanned Probes?
- They don’t have to carry food, water and oxygen
- They can withstand conditions that is very dangerous to humans, e.g extreme heat, cold or radiation levels.
- There is less weight to it so more instruments can fit
- Cheaper since less is spent on safety
- No one gets hurt if it crashes
What are the disadvantages of Unmanned Probes?
- Unmanned probes can’t think for themselves
- A spacecraft can’t do maintenance and repairs, people can
What were the Ancient Greeks’ theory of the structure of the Solar System?
The Sun, Moon, planets and stars orbited the Earth. This is also known as the geocentric model
What was Copernicus’ theory of the structure of the Solar System?
The Earth, stars and other planets orbited the Sun. This is also known as the heliocentric model.
