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Which way does a transverse wave vibrate
Up and down
What are the up and down movement called
Oscillations
What is the movement for longitudinal waves
side to side
what are the 2 parts called to this movement
Compressions and rarefractions
What is amplitude
The gap from the resting point to the wave
What is wavelength
The space between 2 wave peaks next to eachother
How do you measure wavelength in a ripple tank
Place ruler on paper and take a photo and measure 10 waves then divide by 10
How to find out the frequency in a ripple tank
Place a timer and time how many waves pass by in a second or in 10 seconds and then divide by 10
How do you find out speed from a ripple tank
Frequency x wavelength
What are the 3 things that may happen when a wave hits a boundary
Transmitted through material
Absorbed
Reflected
What does it depend on?
Material and wavelength
How do you work out how a ray will be reflected
Draw a dotted line at the surface of the mirror
Measure the angle between the line and incident ray
This is called the angle of incidence
Draw the same angle on the other side of the dotted line and that’s your angle
What is the name for the ray of light
incidence ray
What is the frequency a human ear can hear
20 - 20,000hz
What is important about ultrasound rays
They partially reflect at the boundary between two different density’s
What is the speed of ultrasound in water
1600 m/s
What’s important about working out distance with ultrasound
If the sound waves are going there and back the distance must be halved
What are 2 types of seismic waves
P waves and S waves
What is a p wave
Its longitudinal and can pass through solids and liquids
What is an s wave
Transverse waves and can only travel through solids
What’s faster P or S waves
P
How did scientists find out about the earth having a liquid core
S waves can only travel through solids and there was some parts that s waves couldn’t travel through sowing that there was a liquid core
How did scientists find out about the solid core
As some faint p waves are found in p wave shadow zones
What is an electromagnetic wave
A transverse wave
Where do they transfer energy
From a source of waves to an absorber
What is the order of colours on the spectrum
Red, orange, yellow, green, blue, indigo, violet
What is special about the violet side to the red side
Violet - Higher frequency, shorter wavelength
Red - Lower frequency, Longer Wavelength
What is the abbreviation for the electromagnetic spectrum
Raw meat is very unsanitary eXcept giraffe
What side has the highest frequency and wavelength
Radio - lowest
Gamma - Highest
What is the wavefront
An imaginary line that connects all the same points in a set of waves
What happen when waves enter glass
they slow down
When electromagnetic waves are generated or absorbed….
Changes take place in atoms or in the nuclei of atoms
How can an electromagnetic wave be produced (2 ways)
By a change to the atom
Change to the nucleus eg gamma rays
What is another way a change can happen to an atom
When electromagnetic waves are absorbed
What can ultraviolet waves do to the body
Increase risk of skin cancer and can cause the skin to age earlier
What does ionising radiation mean
Knocking electrons off atoms when waves are absorbed
What can x-rays and gamma rays cause
Mutation of genes which increases risk of cancer
How are radio waves produced
When electrons oscillate in electrical circuits
What are some benefits of radio waves
Travel long distances before being absorbed
They can also be spread out between hills
Why are microwaves used to heat food
As most food contains water particles and water molecules absorb energy of microwaves
What waves are used to go past the earths atmosphere
Microwaves
What is infrared used for
Electrical heaters and ovens as the energy is easily absorbed by the surface of objects
What are some important uses of visible light
Communication and fibre optics
What’s uses of ultraviolet
Energy saving lightbulbs, tanning beds
What are some used of x-rays and gamma rays
Medical imaging
What do light rays do when they change speed going from 1 medium to another
Change direction
What’s the symbol for a convex lens
An arrow
How to draw a ray diagram for a convex lens
Draw a line straight through the centre
Draw a line parallel to the principle axis
Then the line changes direction through the principle focus after passing through the lens
What does it mean when the image is smaller than the object
The image is diminished
What is a real image
When the rays actually meet at a point
What does it mean when the image is bigger then the object
Its magnified
How do you see the image
The distance from the top line to the rays crossing
If an image is more than 2 focal lengths from the lens it is…
Diminished
Inverted
Real
If an object is between 1 and 2 focal lengths the image is…
Magnified
Inverted
Real
How to draw the ray diagram for a magnified image
Draw the ray diagram as normal then draw dotted lines on the other end
What is the opposite of a real image
Virtual image
How to tell what a concave and a convex lens is
concave - bent inwards like a cave
What do concave lenses do to light
Spread it out
How to draw a concave lens ray diagram
Draw a line through the centre
Draw a ray parallel and refract it upwards
What is specular reflection
When all the light rays reflect
Where does this take place and what does it produce
Smooth surface
An image
What is diffuse reflection
When all the light rays are scattered
Where does this take place and what does it produce
Rough surfaces and doesn’t produce an image
What is the best absorber and emitter for infrared radiation
Matt Black surfaces
What does the wavelength and intensity of radiation depend on
Temperature of the object
Very hot objects emit _____ wavelengths than cooler objects
Shorter
A perfect black body…
Absorbs all of the radiation very well and is the best possible emitter of radiation
What is the method to remember the order of planets
My very easy method just speeds up naming
What are the 4 rocky planets
Mercury, Venus, earth, mars
What are the 4 gas planets
Jupiter, Saturn, Uranus, Neptune
What is a moon and what does it do
It is a natural satellite and they orbit planets
How do stars form
Starts as dust and gas called a nebula which is mainly hydrogen
Gravity causes the cloud of dust and gas to collapse causing the temp to rise up to millions of decrees Celsius. This is called a protostar
If the temp is high enough the hydrogen nuclei join together to form helium. This is called nuclear fusion
This now becomes a main sequence star and the forces balance
What happens when the hydrogen in a star runs out
The outward force lessens so the star collapses inwards
The helium nuclei form heavier elements
creating a red giant
What happens when the helium runs out in a red giant
The red giant shrinks and forms a white dwarf cooling down
What happens when all release of energy is stopped
Forms a black dwarf
What happens if a star much bigger than the sun runs out of hydrogen
It becomes a Red Super Giant
Helium nuclei fuse to create heavier elements
What happens when a star stops Nuclear fusion
The star explodes and this is called a supernova
Where is iron formed in stars
In a supernova as the temperature is high enough for it
What are the two things the particles can form after a supernova
A neutron star, Black hole
What is a neutron star
A star consisting of neutrons densely packed together
Light from distant galaxies has a…
Increased wavelength compared to light from closer galaxies
What does red shift tell us
That the galaxies are moving away from each other
Name one type of evidence for the expansion of the universe
Distant galaxies are moving faster than nearby galaxies
What are 2 things that could cause the unexplainability of the expansion of the universe speeding up
Dark Matter and Dark Force
A permanent magnet is a magnet that always has a
Magnetic field
An induced magnet is a
Material that becomes a magnet in a magnetic field
What are the 4 magnetic materials
Iron, steel, cobalt, nickel
How do you draw the magnetic field of a bar magnet
Place the compass near the north pole of the magnet
Draw a cross at the north pole of the compass
Move the compass so the south pole of the compass is on the cross
Draw another cross at the north pol
Continue this till we have a complete magnetic field line
Draw arrows on the line n to s
Continue this at different points of the magnet
How do you find the direction of a magnetic field
Place your thumb pointing towards the direction of conventional current then curl your fingers round, your fingers are the direction of magnetic field
What is this called
A solenoid
What happens when you turn on a current with a solenoid
Strong and uniform magnetic field inside the solenoid
What are the 3 ways to increase the strength of a magnetic field produced by a solenoid
Increase size of current
Increased number of turns in the coil
Place iron inside it
What is an electromagnet
A solenoid with an iron core
What is the motor effect
When a wire with a magnetic field is placed in a magnetic field causing it to feel an upwards force
How does Flemings left hand rule work
Place your thumb, first and middle finger at right angles with each other. Then place the first finger in direction of field from N to S
Then place your middle finger in direction of current from + to -.
Your thumb shows the direction of force
What is important about direction of current in the generator effect
The direction of the current switches when the direction of movement switches
What makes the induced potential difference and current larger
Stronger magnetic field
Move the wire more rapidly
More turns in the coil
Name 6 scalar quantities
Mass, Temperature, Speed, Energy, Distance, Time
What is a scalar quantity
Size only and no direction
