1
Q
What are waves
A
- Waves carry energy from one place to another , they can also carry information
- Waves do not transfer any matter
2
Q
What are the types of wave and whats the difference
A
- Waves may be either transverse or longitudinal
3
Q
What s a transverse wave
A
- Transverse waves babe sideways vibrations
- The vibrations are at perpendicular angle to the direction of energy transfer
- Most waves- include, ripples in water - is not water that moves
4
Q
What is a longitudinal wave
A
- They have vibrations parallel to the energy transfer. They compress and refract
- An example os sound waves
5
Q
What are oscillation
A
- The movements, vibrations, in waves
6
Q
What is the equation for wave speed
A
- Wave speed = Frequency x wavelength
v = f x w
v- speed- m/s
f- Frequency- hertz- Hz
w- wavelength- m
7
Q
What is amplitude
A
The amplitude of a wave is the maximum displacement of a point on a wave from its undisturbed position
8
Q
What is wavelength
A
- Wavelength of a wave is the distance from one point on one wave to the equivalent point on the adjacent wave
- The distance between two waves
9
Q
What is meant by frequency
A
- Frequency of a wave is the number of waves that passes through a point per second
10
Q
What is meant by wave period
A
Amount of time it takes for a full cycle of the wave
period = 1/ frequency- given
11
Q
How do you measure the speed of sound waves
A
- Set up the oscilloscope so the detected waves at each microphone are shown as operate
- Start with both microphones next to the speaker, slowly move one away until two waves are aligned on the misplay but have moved exactly one wavelength apart
- Measure the distance between the microphones to find one wavelength
- Use formula to find speed. Frequency is what you set the generator at
- The speed is around 330m/s-check
12
Q
What is the method to find the speed of ripples on water
A
- using single generator attached, you can create water at a set frequency
- Use a strobe light to see wave crests
- Increase frequency of strobe light until patter on screen appears to stop moving- When this happens frequency of stone light is equal to frequency of waves
- Strobe allows measure still pattern
- Distance between each shadow light is one wavelength. measure distance between 10 and divide to find average
- Calculate speed of waves
13
Q
-What are electromagnetic waves-
A
- Traverse waves that transfer energy from source to an absorber
- Forma continuos spectrum
- All types of electromagnetic waves travel at the same speed in a vacuum
14
Q
What is the electromagnetic spectrum
A
- Electromagnetic Waves are organised are grouped into spectrum
- Organised by frequency and wavelength
- Goes from from short to high wavelength
- Our eyes only detect visible light
15
Q
List all the electromagnetic waves from shortest to longest
A
- Radio
- MICrowaves
- Infrared
- Visible light
- Ultraviolet
- X rays
- Gamma rays
16
Q
What are some examples of electromagnetic waves
A
- Camp fire- transfers emerge to its surroundings using infrared radiation
- Radio waves transfer kinetic energy stores of electrons in radio receivers- generates electrical current
17
Q
What are the three ways substances may deal with electromagnetic waves
A
- Absorb- transfer to other energy stores.
- Transmitted- wave carries on traveling.
- Reflected- where the incoming ray is sent back- echo
- Depends on wavelength and material
18
Q
-Why does refraction happen
A
- When a wave crosses a boundary it changes speed
- IF it is traveling along the normal it will not be refracted-
- IF it hits it at an angle it changes direction and it is refracted
- Wavelength changes, frequency stays
19
Q
What factors change the level of refraction
A
- IT depends on the change in speed between the boundary
- The higher the density the slower the wave travels- general
20
Q
What is optical density
A
- TH measure of how quickly light can travel through
21
Q
How doHow do wave front diagrams show refraction
A
- Wave front is a line showing all of the point on a wave that are in the same position after a given number of wavelengths
- When a wave crises a boundary at an angle only part of it crosses it first
- IF its going into a denser material that part goes slower than the rest
- Sop by the time the whole wave has passed through the faster part will have traveled further than the slower part
- The difference in distance traveled is what causes the bend
- Simply- the part still in the less dense area will move faster and a bend will show
22
Q
- How are radio waves made-
A
- BY oscillation in electric and magnetic field.
- Radio waves are absorbed and may create an alternating current with the same frequency as the radio waves
- They can create oscillations
23
Q
How can you produce radio waves using an alternating circuit
A
- The objects that oscillate to create the radio waves is called a transmitter
- When radio waves in transmitter are received they are absorbed and transferred to electrons
- Causes them to oscillate and alternating circuits created
- Same frequency
24
Q
What are radio waves main use
A
Mainly used for communication- radio and TV
- Refracted around curved surface of earth - Long long wave up to 10km
25
What are microwave waves use
Mainly uses include- Satellite and cooking food
- Need to use microwaves that can pass through earth watery surfaces
- Microwave use different wavelength - Need to be absorbed by water in food - Penetrate a few cm and water transfers hear
26
what are inferred radiation's uses
Used to increase and monster temperatures- Electrical heater , cooking, infrared cameras
- Camera detects inferred camera, turn into electrical signal. Displayed
- Absorbing inferred causes increasing temp- food temp increases and its cooked
- Same way with heaters- long wire is heated and emitted and absorbed
27
- What is visible lights uses
- Fiber optic communications
- Optical fibres are thin glass or plastic fibres that carry data over long distances
- Refraction of light rays bounced back until reach end of fibre
- Not easily aboirbed or scatteed
28
What are ultraviolet radiation
- Fluorescence- where uv radiation is absorbed and visible light emitted-
- Fluorescent lights generate uv which is absorbed and re-emmited- energy efficient
- Suntain- UV ;a,ps
29
What are the uses of X rays and Gamma rays
- To see for broken bones
- Easily pas through fees, but don't mass through bone
- Amount of radiation absorbed gives x ray photo
- Cancer- high doses of rays kill living cells - directed towards cancer cells.
- Medical tracer- gamma emitting source injected and tracked- refracted
30
WHAT rays can have hazardous effects
- X-rays, gamma and Ultraviolet
- Human body tissue
- Depends on type and dose.
31
What effect does change in nuclei and atoms
- Can result in electromagnetic waves being generated and absorbed over wide frequency range
- Gamma rays originate from changes in Nuclei of atom
32
- How can the surface of an object have an effect on how much inferred radiation it emits- practical
- A Leslie cuve is a hollow, watertight metal cube who's four vertical faces have different surfaces
- Place empty Leslie cube on heat proof mat and fill with boiling water- wait to hear up
- Hold thermometer to each surface and see that all sides have the same temp
- Hold inferred detector a set distance away from surface and record how much IR radiation tit emits- repeat using the same set distance
- Should see more inferred from black surface than white one. And more from matt than shiny
- Repeat to test reliability
