P12 Flashcards
What can waves be used for?
To transfer energy and information
How do transverse waves oscillate?
Perpendicular to the direction of energy transfer of the waves
Name 2 examples of transverse waves?
Ripples of a surface of water and all electromagnetic waves
How do longitudinal waves oscillate?
Parallel to the direction of energy transfer of the waves,
Name an example of longitudinal waves?
Sound waves in the air
What do mechanical waves need?
A medium( substance) to travel through
Are mechanical waves transverse of longitudinal?
Both
What do electromagnetic waves not need?
A medium
What is the amplitude of a wave?
It’s peak to mid point
What is a wavelength?
The distance from a point of the wave to the equivalent point on the adjacent wave
What is the bottom of a wave called?
Trough
What does the bigger the amplitude of a wave show?
The more energy the wave carry
What is the wave speed equation with units?
Wave speed( m/s) = frequency( hertz,Hz) X wavelength(m)
What is a waves frequency?
The number of waves passing a point per second
What is the speed equation?
Speed= distance divided by time
In reflection and refraction practical, what do you use to create a beam of light?
A ray box, lens and slit
What are the steps for reflection and refraction practical?
1- Draw a straight line down the middle of a bit of paper
2- Use a protractor to draw a line at right angles, this is the normal
3- Place a glass block against the first line so the normal is near the centre of the block
4- Draw around the glass block
5- Turn of all lights in the room
6- Use the ray box to direct a ray of light so it hits the block at the normal
7- This is the incident ray
8- The angle between the incident ray and the normal is the angle of incidence
9- Mark the path of the reflected ray aswell as the transmitted ray
10- Turn on the lights, remove the ray box and remove glass block
11- Draw in incident, reflected and transmitted ray
12- Draw a line of the path through the glass block from incident to transmitted
13- Use a protractor to measure angle of incidence and angle of reflection
14- Then the angle of refraction
15- Repeat but use different materials instead of glass
What are sound waves?
Vibrations that travel through a medium
What can’t sound waves travel through?
A vacuum eg outer space
State 3 examples of how you could investigate waves?
A ripple tank
A stretched string
A signal generator
When does the pitch of a note increase?
If the frequency of the sound waves increase
When does the loudness of a note increase?
If the amplitude of the sound waves increases
What do sound waves cause the ear drum to do?
Vibrate, this sends signals to the brain
What are ultrasound waves?
Sound waves of a frequency above 20kHz
Where are ultrasound waves partly reflected?
At a boundary between 2 different types of body tissue
How are ultrasound waves used to calculate distance?
When they are reflected at doundaries they are timed, and the timings are used to calculate distance
Why is an ultrasound scan safer than an x-ray?
As it is non-ionising
What is the depth of the boundary below the surface equation with units?
Depth of the boundary below surface(m) = 0.5 X speed of ultrasound waves(m/s) X time taken(s)
What are seismic waves?
Waves that travel through the earth
Where are seismic waves produced?
In an earthquake and spread out from the epicentre
Are primary seismic waves longitudinal or transverse waves?
Longitudinal
Are secondary seismic waves longitudinal or transverse waves?
Transverse
What are the layers of the earth?
Inner core, outer core, mantle, crust
What are primary waves?
Waves that push or pull on material as they move through the earth
What are secondary waves?
Waves that shake the material that they pass through inside the earth from side to side
