Waves Flashcards
A danger of ultraviolet?
Damage to skin cells, blindness
A use of gamma rays
Sterilising food and medical equopment
A Mexican wave is an example of what type of wave?
Transverse
List three differences between light and sound waves
SOUND
- Longitudinal
- 340 m/s in air
- Needs a medium
LIGHT
- Transverse
- 300,000,000 m/s
- No need for medium
Wave speed =
Wave speed m/s = frequency Hz x wavelength m
A use of infrared
Heaters, night bision
Speed that infra red radiation travels through space?
300,000,000 m/s
What is the word given to the weakening of signals over distance?
Attenuation
All waves, but digital waves are easier to interpret once they have been amplified
What influences how much a wave is diffracted through a gap?
The wavelength of the wave and the width of the gap
A use of visible light?
Optical fibres, photography
How does the shape of a sound wave affect its pitch?
High frequency and short wavelength = high pitch
Low frequency and long wavelength = low pitch
What is the order of the magnetic spectrum?
Radio Micro Infrared Visible Ultraviolet X Gamma
Use of radio waves?
Broadcasting and communications
What is the frequency of a wave?
The number of waves passing a point per second
Hertz or s-1
What are longitudinal waves?
The vibrations/ displacements are in same direction (plane) as its direction of trabel
Danger of infrared
Skin burns
Period of a wave
The time taken for one wavelength to pass a point
Measured in seconds
What is it called when two identical waves meet and cancel each other out?
Destructive interference
Transverse waves
The vibrations/ displacements are at right angles to its direction of travel
Danger of microwaves
Internal heating of body tissie
Amplitude of a wave
The maximum displacement, measured in metres
What is refraction?
The bending of light rays as they go from one medium to another
Use of microwaves
Cooking, satellite transnissions
Danger of gamma rays?
Cancer/ mutation
Total internal reflection
When a ray reflects 100% from the internal surface of glass or pladyic
Which has the most energetic protons?
Gamma, ultraviolet or radio
Gamma
How are frequency and time period related?
Frequency = 1/ time period
In reflection, the angle of incidence=?
The angle of reflection
What is the speed of a wave with a wavelength of 2 metres and frequency of 6 Hz?
12 m/s
What speed to radio waves travel through space?
300,000,000 m/s
Light can travel through a vacuum. Can sound waves?
No
What is the critical angle?
The angle at which the light begins to totally internally reflect OR the angle of incidence which gives an angle of refraction of 90 degrees
Sin c =
1/ n
The speed if light?
300,000,000 m/s
How does the shape if a sound wave affect its volume?
Large amplitude = loud sound
Small amplitude= quiet sound
How are digital signals better than analogue
They can carry more info
The effect of noise and attenuation can easily be cleaned up
A distorted signal is much easier to interpret than a distorted analogue one
Waves transfer…
ENERGY
Use of X rays
Looking at internal structure of objects and bodies
n is what?
Refractive index
What is the range for human hearing?
20-20,000 Hz
Signals can pick up random additions on their way to the receiver, making the quality poorer. What are these random additions?
Simply just noise
