Waves Flashcards
What is frequency measured in?
Hertz (Hz)
How are waves formed and what do they transport?
Waves are formed by vibrations and they transport Energy from one place to another
Frequency is equal to
No. of Waves / Time
Longitudinal Waves
Particles vibrate back and forth parallel to the direction in which the wave is travelling
Examples of Longitudinal Waves
Sound + Ultrasound
Transverse Waves
Particles vibrate up and down perpendicular to the direction in which the wave is travelling
Examples of Transverse Waves
All Electromagnetic Waves, Water waves, S-Type Earthquakes
(Wave Equation) Speed is equal to
Frequency x Wavelength (v = f x λ)
What is Ultrasound
Frequencies that are higher than 20,000Hz
What is the audible human hearing range?
20Hz - 20,000Hz
What are some Ultrasound applications?
In Industry - Detecting Faults in Metals
In Medicine - Scanning soft tissues to diagnose cancers
Sonar and radar both use
the principle of echo-location to detect objects
Sonar is
Sound Navigation and Ranging (sound waves are used to locate objects under water)
Radar is
Radio Detecting and Ranging - (EM waves are used to detect aircrafts and ships)
Distance =
Speed x Time
The Use of Gamma
Used to kill cancer cells and sterilize medical equipment
The Use of X-Ray
To Diagnose Broken Bones
The Use of UV (Ultraviolet)
Detect Forged Bank Notes
The Use / Dangers of Visible
Used for Human Vision, Photography / Can cause Snow Blindness
The Use / Dangers of Infrared
Toasters, Ovens, Tv remotes / Damages cells by Burning
The Use / Dangers of Microwaves
Used in Mobile Phones + Satelites / Internal Heating of Body Tissues (cause eye Cataracts)
The Use / Dangers of Radio
Tv and Radio Communications / No known Dangers
The Dangers of Gamma, X-Ray and UV (Ultraviolet)
Can Disrupt DNA and cause Cancers
Higher frequency waves cause ____ damage to cells?
More
All Electromagnetic waves are
Transverse
What speed do Electromagnetic waves travel at?
300 Million m/s in a Vacuum
How do you measure angle of incidences and reflections?
From The Normal
Angle of Incidence =
Angle of Reflection
What is refraction?
The bending of light as it travels from one material to another
Why does refraction happen?
Because light travels at different speeds in different materials.
Air = 300 million m/s
Water = 225 million m/s
Glass = 200 million m/s
What is Dispersion (of white light)?
The splitting of white light into the colours of the visible spectrum
Why does dispersion happen?
Each colour travels the same speed in air but differently in glass
Colour order of refractions
Red, Orange, Yellow, Green, Blue, Indigo, Violet
What is Ohms Law?
The current through a wire is directly proportional, to the voltage across it, provided that the temp remains constant.
Voltage =
Current x Resistance
Why does resistance increase in a lamp over time?
Becomes the lamp becomes hotter
