Waves Flashcards
Transverse wave?
Perpendicular to the direction of travel and energy transfer of the wave
Longitudinal wave?
A wave with oscillations that are parallel to the direction of energy transfer
What is compression?
Where particles moast concentrated within a wave
What is rarefraction?
Regions where particles are less concentrated in a wave
Frequency?
The number of oscillations (complete waves) in 1 second.
(hertz, Hz)
What is the volume and pitch of a soundwave?
Volume is amplitude
Pitch is Frequency
What is the range of ultrasound and infrared waves?
Ultrasound is 20KHz+
Infrared is 20Hz-
Why are soundwaves faster in solids than in gases
Particles are closer together therefore they will collide more frequently than in a gas causing the wave to travel quickly
Why can’t soundwaves be transferred in space?
Space is a vaccum without particles
What is an echo?
Reflection of a soundwave
How can an echo be used to detect how far an object is?
Sound is made
Reflected sound is detected by reciever
Time taken for echo to get to reciever and speed of sound is used the calculate distance
Sonar distance = ½×speed×time
How are sonars used to detect depth of water under boat?
Ultrasound is emitted from boat and time taken for echo to be received is measured and used with speed to calculate distance
How is an ultrasound used?
Produce images or organs.
Sends out pulses of ultrasound and they reflect from different boundaries in the pathway of the pulse. Probe slowly moved to produce image.
Advantage to ultrasound?
No radiation so baby is not harmed as not ionising
What are rod and cone cells functions?
Rod cells are responsible for detecting movement in low light vision
Cone cells are active at bright light levels and are responsible for colour vision
Uses & safety precautions for radio waves?
Satellite transmissions
Broadcasting
Heat so penetrating ppl interal parts
Uses and safety precautions for microwaves?
Cooking
Communication
Penetrating heat ppl internal parts
Uses and precautions for infrared?
Remotes
Thermal imaging
Can burn skin so fire fighters wear reflective silver suit
Uses and precautions for visible light?
Vision
Photography
High levels can cause permanent or temporary blindness
Uses and precautions for UV?
Security tags
Sun tanning
Skin cancer/age skin so use sun cream
Uses and precautions for X rays?
Images of internal body parts
Security scans
Cancer over long period due to constant absorption
Ionising
Uses and precautions for gamma rays?
Sterling food and medical instruments
Radiotherapy
Cancer due to mutation
Ionising so badges manage your exposure
Similarities of X rays and gamma rays?
Both short wavelength
Very penetrating
Stopped by thick plate of lead
Differences of gamma rays and X rays?
Gamma rays are more penetrating
What do ground waves do?
They are long wavelength radio waves that follow the curvature of the earth. Used in submarine communication
What are AM waves
They are short waves that reflect in the ionosphere (fluctuating amplitude). Used in aviation communications
What are FM waves?
They are space waves that rely on the line of sight to be recieved. This means placed on hills for effective transmission. Used for FM radio
What is optical fiber?uses?
Light transmission (reflected within) through glass. Transparent so little energy is lost and can bend. Infrared radiation
Vitual image?
An image that is formed when light rays appear to come from a focus point that they dont pass through
What is diffuse scattering?
Reflection from a rough surface
What happens is a ray hits a medium at 90⁰?
It will face no change in direction and go along the normal line but will have a change in speed
What happens at a medium with low to high optical density?
Angle of incidence is bigger than angof refraction
What happens at a medium with high to low optical density?
Angle of incidence is less than the angle of refraction
What is a red filter?
Absorbs all colour except red that is transmitted
What are the primary and secondary colours?
Primary - red blue green
Secondary - yellow cyan magenta
What is specular reflection?
reflection from a smooth, flat surface in a single direction
What does a red, white and black object do?
Reflect only red light
Reflect all light
Absorb all light
What is a black body?
Valerie 🤣
A perfect black body is an object which absorbs all the radiation that reaches it therefore good emitter of radiation
