P6 Flashcards
What is the definition of a wave?
A wave transfers energy from one place to another without transferring any matter.
What happens to particles in a medium when a wave travels through it?
The particles of the medium vibrate.
What is a medium in the context of waves?
A medium is whatever the wave is travelling through (e.g., water, air).
What do particles do as they vibrate in a wave?
They transfer energy between each other.
Do particles in a medium move with the wave?
No, overall, the particles stay in the same place.
What type of wave is created when you drop a twig into calm water?
Ripples spread out.
What are the two main types of waves?
Transverse waves and longitudinal waves.
In which type of wave are vibrations perpendicular to the direction of energy transfer?
Transverse waves.
Give two examples of transverse waves.
- Light
- Ripples on water
- Waves on a string
In longitudinal waves, how are the vibrations oriented in relation to energy transfer?
The vibrations are in the same direction as the energy transfer.
What are the two key features of longitudinal waves?
- Compressions
- Rarefactions
What is an example of a longitudinal wave?
A sound wave.
What does the term ‘displacement’ refer to in wave physics?
How far a particle on the wave is from its rest position.
What is amplitude in the context of waves?
The maximum displacement of a point on the wave from its undisturbed (rest) position.
What is wavelength?
The distance between one point on a wave and the same point on the next wave.
How is frequency measured?
In hertz (Hz), where 1 Hz is 1 wave per second.
What is the period of a wave?
The amount of time it takes for one complete wave to pass a certain point.
True or False: Waves carry matter with them.
False.
How do you calculate the period of a wave from its frequency?
T = 1 / f
T is the period in seconds, and f is the frequency in Hertz (Hz).
What is the relationship between wave speed, frequency, and wavelength?
Wave speed (m/s) = frequency (Hz) × wavelength (m)
This equation applies to all types of waves.
What is the formula to calculate the wavelength from wave speed and frequency?
λ = v / f
λ is the wavelength, v is the wave speed, and f is the frequency.
What is the speed of radio waves in air?
3 × 10^8 m/s
This is the speed used to calculate the wavelength of radio waves.
What is the formula to find the speed of sound waves passing through air?
v = f × λ
v is the speed, f is the frequency, and λ is the wavelength.
What equipment is used to measure the speed of sound in the described method?
Oscilloscope and microphones
An oscilloscope displays waves, and microphones detect the sound waves.
What is the typical speed of sound in air?
Around 330 m/s
This value is used as a reference to check the results of measurements.
Fill in the blank: The wave speed is how fast the wave is _______.
moving
True or False: The frequency of a wave is inversely related to its period.
True
As frequency increases, the period decreases and vice versa.
If a wave has a speed of 0.15 m/s and a wavelength of 7.5 cm, how would you calculate its frequency?
f = v / λ
Convert 7.5 cm to meters for calculations.
What is the first step in measuring the speed of sound using an oscilloscope?
Connect two microphones to the oscilloscope
What should you do after connecting the microphones and the oscilloscope?
Connect a signal generator to a speaker
What indicates that the microphones are exactly one wavelength apart?
The waves on the oscilloscope line up again
What is the purpose of moving one microphone away from the speaker?
To measure the wavelength of the sound waves
The frequency of a wave is measured in _______.
Hertz (Hz)
What is the relationship between frequency and period?
Period is the inverse of frequency
What do you need to measure the distance between the microphones for?
To find the wavelength
What is the formula to calculate wave speed?
v = f * λ
Where v is wave speed, f is frequency, and λ (lambda) is wavelength.
How can you determine the wavelength of water waves in an experiment?
Count the distance across 10 gaps between shadow lines and divide by 10
This method allows for accurate measurement of wavelength without disturbing the waves.
What is the frequency of a wave if the period is 2 seconds?
0.5 Hz
Frequency (f) is the reciprocal of the period (T), so f = 1/T.
Fill in the blank: The distance between each shadow line is equal to one _______.
wavelength
What should be done to ensure accurate measurements when investigating waves?
Conduct the experiment in a darkened room
This helps in clearly observing shadows cast by the ripples.
True or False: The vibration generator can be used to create waves on a string.
True
How do you calculate the wavelength when you have a whole number of wavelengths on the string?
Divide the length of the whole vibrating string by the number of wavelengths
Each vibrating loop represents half a wavelength.
What type of waves are suitable for measurement in this experiment?
Sound waves, ripples, and waves on strings
These are easy to create and observe.
Fill in the blank: If there are 3 loops on the string, there are one-and-a-half _______.
wavelengths
What is the first step in the practical investigation of waves?
Attach a signal generator to the ripple tank dipper
What is the benefit of using a ripple tank for wave experiments?
It allows you to measure the wavelength without disturbing the waves.
What should you do if you struggle to measure the wavelength directly?
Take a photo of the shadows and ruler to find the wavelength from the photo instead.
What should be adjusted to observe a clear wave on the string?
The frequency of the signal generator
True or False: Each vibrating loop on the string represents one whole wavelength.
False
Each vibrating loop represents half a wavelength.
What is the significance of measuring the distance between shadows in wave experiments?
It helps accurately determine the wavelength of the waves.
What is refraction?
When a wave crosses a boundary between two materials, it can change direction.
Refraction occurs when waves meet a boundary at an angle.
Under what condition do waves get refracted?
Waves are only refracted if they meet the boundary at an angle.
The degree of refraction depends on the materials involved.
What is the ‘normal’ in ray diagrams?
The ‘normal’ is a line drawn at right angles to the boundary between two materials.
It helps in measuring angles of incidence and refraction.
Define the angle of incidence.
The angle between the incident ray and the normal.
It is measured using a protractor.
What is the angle of refraction?
The angle between the refracted ray and the normal.
This angle is formed after the wave crosses into the second material.
How do you construct a ray diagram for a refracted light ray?
1) Draw the boundary
2) Draw the normal
3) Draw the incident ray
4) Measure the angle of incidence
5) Draw the refracted ray.
Ensure to use a protractor for accuracy.
What happens when a ray of light meets a boundary at an angle of incidence of 55° and has an angle of refraction of 35°?
A ray diagram can illustrate the path of the light ray as it refracts at the boundary.
This demonstrates the principles of refraction in action.
True or False: Refraction is a common behavior of waves.
True.
Understanding refraction is essential before proceeding to more complex wave behavior.
What is the primary factor that affects the degree of refraction?
The two materials the wave is passing between.
Different materials have varying refractive indices.
Fill in the blank: The _______ is the ray that meets the boundary at the normal.
[incident ray].
The incident ray is crucial for determining the angles of incidence and refraction.
What are electromagnetic (EM) waves?
Waves that travel at the speed of light and vary in wavelength and frequency.
EM waves include radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays.
List the types of electromagnetic waves.
- Radio waves
- Microwaves
- Infrared
- Visible light
- Ultraviolet
- X-rays
- Gamma rays
Each type has different properties and applications.
What is the significance of the electromagnetic spectrum?
It is a range of all types of EM radiation, split into different categories based on wavelength.
The spectrum helps in understanding the behavior and applications of different EM waves.
Fill in the blank: Our eyes can detect _______ changes in electromagnetic radiation.
[visible light].
Visible light is a small part of the EM spectrum that is detectable by the human eye.
What is the main characteristic of electromagnetic (EM) waves?
They transfer energy from a source to an absorber
A campfire is an example of a source transferring energy through infrared radiation.
What type of EM wave is emitted by a campfire?
Infrared radiation
Infrared radiation is a type of electromagnetic wave that gets absorbed by objects, warming them up.
What is the speed of EM waves in air or a vacuum?
Much faster than the speed of sound in air
All EM waves travel at the same speed regardless of their wavelength or frequency.
How do sound waves compare to light waves in terms of wavelength and frequency?
Sound waves have a much bigger wavelength and a much lower frequency than light
This difference in properties affects how we perceive sound and light.
What is a continuous spectrum in the context of EM waves?
A range of EM waves of every wavelength
The spectrum is divided into seven groups based on wavelength and frequency.
What are the seven groups of the electromagnetic spectrum?
- Radio waves
- Microwaves
- Infrared waves
- Visible light
- Ultraviolet waves
- X-rays
- Gamma rays
Each group has different wavelengths and frequencies.
What part of the EM spectrum can humans detect?
Visible light
Our eyes are only sensitive to a small part of the entire electromagnetic spectrum.
What causes the production or absorption of EM radiation in atoms?
Changes in atoms and their nuclei
For example, electrons moving between energy levels or changes in the nucleus can produce gamma rays.
How can atoms generate EM waves?
By producing or absorbing different frequencies of EM waves
Each different change in an atom results in a different frequency of EM radiation.
Fill in the blank: The order of EM waves can be remembered with the phrase ‘Rock Music Is Very Useful for ______ with Goats.’
eXperiments
This mnemonic helps in recalling the sequence of electromagnetic waves.
State the type of electromagnetic wave that has the lowest frequency.
Radio waves
Radio waves have the longest wavelength and lowest frequency in the electromagnetic spectrum.
Name the section of the electromagnetic spectrum that humans can see.
Visible light
This section includes all the colors visible to the human eye, ranging from red to violet.
What are radio waves mainly used for?
Communication
Radio waves are essential for transmitting radio and TV signals.
What type of radio waves are used for FM radio and TV?
Very short wavelength signals
These signals require direct sight of the receiver.
How do longer wavelength radio waves compare to shorter ones?
They can travel further
Longer wavelengths can send radio signals around the world.
What are microwaves used for in communication?
Satellites
Examples include satellite TV and satellite phones.
Describe the process of satellite communication.
Signal sent to satellite dish, satellite sends signal back to Earth
Ground satellite dishes receive the signal.
How do microwave ovens cook food?
By emitting microwaves absorbed by water
The energy heats up the food quickly.
What does infrared radiation (IR) do?
Transmits energy that warms objects
All objects emit IR radiation; hotter objects emit more.
How can infrared cameras be useful?
They detect IR radiation and create images
Useful for identifying energy loss in buildings.
What is one application of infrared radiation?
Warming things
Electric heaters release IR radiation to warm rooms.
Fill in the blank: UV lamps can be used for _______.
[disinfection or curing processes]
UV light has various applications including sterilization.
What is the use of X-rays?
To pass through materials for imaging
Commonly used in medical diagnostics.
How does gamma radiation compare to X-rays?
Gamma radiation is more penetrating
Used in cancer treatment and imaging.
What does the color detected in infrared imaging indicate?
Amount of IR radiation detected
Redder colors indicate more IR radiation.
True or False: Infrared radiation can only be used for cooking.
False
It can also be used for heating and in electric heaters.
State one use of radio waves.
Radio and TV signals
Radio waves are essential for various communication technologies.
What do optical cables use to send data?
Visible light
Optical cables carry data over long distances using light rays that bounce back and forth along the fiber.
How do optical cables transmit information?
As light rays
Information is sent as light rays that travel through glass fiber.
What happens when materials absorb UV light?
They give off visible light
This property can be harnessed for various applications, such as energy-efficient lighting.
List two uses of UV radiation.
- Energy-efficient lights
- Security pens
UV radiation is utilized in energy-efficient lighting and for marking property with invisible ink that glows under UV light.
What does UV radiation from the Sun cause?
A suntan
UV radiation is responsible for tanning skin, and UV lamps can mimic this effect.
What is one medical use of X-rays?
Create X-ray images
X-rays pass through flesh but not bones, allowing doctors to check for broken bones.
How can X-rays be used in cancer treatment?
To kill cancer cells
X-rays can be aimed at cancer cells to destroy them.
What is a use of gamma rays in medicine?
Sterilize medical equipment
Gamma rays can remove germs from medical tools by blasting them with radiation.
What do gamma rays help track in the body?
Medical tracers
Gamma rays can be used in tracers to monitor the function of organs.
True or False: X-rays can see through metal.
False
X-rays pass easily through flesh but not through metal.
Fill in the blank: Ultraviolet radiation is produced by the _______.
Sun
The Sun naturally emits ultraviolet radiation.
What factors influence the amount of infrared radiation an object emits?
Temperature and surface characteristics
Surface characteristics include roughness, shininess, and color.
What is a Leslie cube?
A hollow, metal cube used to investigate infrared radiation emission
The Leslie cube has four side faces with different surfaces.
List the types of surfaces found on a Leslie cube.
- Matt black paint
- Matt white paint
- Shiny metal
- Dull metal
Each surface emits infrared radiation differently.
Fill in the blank: The face of the Leslie cube that gives off the most infrared radiation is determined by _______.
[recording the IR radiation detected]
What should you feel to determine which surface emits more infrared radiation during the experiment?
Place your hand near each surface without touching it
This allows you to feel the heat emitted by each surface.
True or False: Shiny surfaces emit more infrared radiation than matt surfaces.
False
Matt surfaces typically emit more IR radiation than shiny surfaces.
What is the expected outcome when comparing the infrared radiation emitted by a black surface and a white surface?
The black surface emits more infrared radiation than the white surface
This is due to the properties of color and emissivity.
Describe the procedure for using a Leslie cube to investigate infrared radiation emission.
- Place the cube on a heat-proof mat
- Draw a square 10 cm from all faces
- Fill the cube with boiling water
- Use an infrared detector 10 cm away from a vertical face
- Record the IR radiation detected
- Repeat for each face
This method allows for a direct comparison of different surface emissions.
What role does temperature play in infrared radiation emission?
It determines the amount of infrared radiation an object emits
Higher temperatures generally lead to greater IR emission.
What is the main objective of the melting wax experiment?
To investigate the absorption of infrared radiation by different materials.
The experiment demonstrates how surface color affects infrared absorption.
What materials are needed for the melting wax trick experiment?
- Bunsen burner
- Candle wax
- Metal plates
- Metal balls
Ensure the metal plates are identical except for their back surface.
What should be the difference between the two metal plates used in the experiment?
One plate should have a black back and the other a white back.
The color difference is crucial for observing variations in infrared absorption.
How should the metal balls be attached to the metal plates?
Stick a metal ball to each identical side of the metal plates with hot candle wax.
Allow the wax to cool and harden to secure the balls.
What is the procedure after setting up the experiment with the Bunsen burner?
Face the back of the plates towards the flame and ensure they are equidistant from it.
This setup is crucial for a fair experiment.
What is recorded during the experiment?
Which metal ball falls first.
This indicates which plate absorbed infrared radiation more effectively.
What happens to the candle wax during the experiment?
The candle wax starts to melt as it absorbs thermal energy from the infrared radiation.
This melting causes the metal balls to fall.
Which ball is expected to fall first and why?
The ball on the plate with the black back falls first because the black surface absorbs infrared radiation better than the white surface.
This result illustrates the effect of surface color on thermal absorption.
True or False: The color of the surface affects the absorption of infrared radiation.
True
The experiment demonstrates that darker surfaces absorb more infrared radiation.
What can happen when EM radiation enters living tissue?
It can be dangerous
What types of high-frequency waves can cause damage?
UV, X-rays, and gamma rays
What are two effects of UV radiation on the skin?
- Sunburn
- Faster skin aging
What more serious effects can UV radiation cause?
- Blindness
- Higher risk of skin cancer
What type of radiation are X-rays and gamma rays classified as?
Ionising radiation
What can ionising radiation do to atoms?
Knock electrons off atoms
What can the destruction of cells or mutation of genes from ionising radiation lead to?
Cancer
How is radiation dose measured?
In sieverts (Sv)
What is the relationship between millisieverts and sieverts?
1000 mSv = 1 Sv
What does the risk from radiation depend on?
- Total amount of radiation absorbed
- How harmful the type of radiation is
In a CT scan, which part of the body receives a higher radiation dose, the head or the chest?
The chest
How much radiation dose (in mSv) does the chest receive compared to the head during a CT scan?
8.0 mSv for chest, 2.0 mSv for head
How much more likely is a patient to be harmed from a chest CT scan compared to a head CT scan?
Four times more likely
True or False: X-rays are considered high risk and should be avoided completely.
False
Fill in the blank: A sievert is a measure of the risk of harm from _______.
radiation exposure
What are two effects of a person being exposed to too much UV radiation?
- Sunburn
- Skin cancer
What property of gamma rays and X-rays makes them dangerous to humans?
They are ionising radiation
