Waves, sound and light Flashcards
Explain what a wave is?
Transmits energy
Particles of the medium oscillate
Particles move up and down or back and forth but don’t move
What is the definition of oscillation?
the movements of particles to and fro between two points
What is the definition of amplitude?
The maximum displacement of a particle from it’s rest position
What is the difference between a crest and a trough?
The crest is the highest point of a wave and the trough is the lowest point of a wave
What is the definition of the term superposition?
The algebraic sum of the amplitudes of two waves that occupy the same space at the same time
What is the definition of constructive interference?
The crest of one wave overlaps with the crest of another wave to produce an increased amplitude
What is the definition of destructive interference?
The crest of one wave overlaps with the trough of another to produce a decreased amplitude
What happens after superposition?
the waves continue in the original direction of motion with it’s original amplitude
What is the definition of the term transverse waves?
A wave in which the particles of the medium vibrate perpendicularly to the direction of motion of the wave
What happens in a transverse wave?
The particles move up and down while the wave moves forward, particles don’t travel with the wave
What is the definition of a longitudinal wave?
A wave in which the particles of the medium vibrate parallel to the direction of motion of the wave
What is the definition of the term compression?
A region of high pressure in a longitudinal wave
What is the definition of the term rarefraction?
A region of low pressure in a longitudinal wave
What is the definition of the term period?
Time taken for one complete oscillation
What is the definition of frequency?
Number of oscillations for every one second
What is oscillations measured in?
hertz (Hz)
What is a wavelength?
the distance a wave travels in one oscillation
Explain sound as a wave?
Longitudinal wave
As pressure changes, particles transfer energy
Can be transferred through solid, liquids and gases
Which objects absorb and reflect sound?
Hard objects reflect sound
Soft objects absorb sound
What is pitch?
How high or low a note is
Depends on frequency
Higher frequency = higher note
What is loudness?
How loud a note is
Depends on amplitude
Higher amplitude = higher sounds
What is the difference between noise and a music note?
A music note is a sound caused by regular vibrations and a noise is irregular vibrations with a mixture of different frequencies
What is wave speed?
The distance travelled by a point on a wave per unit time
What kind of waves are sound waves?
Longitudinal waves
What happens to the particles in a sound wave?
As the pressure changes, particles transfer energy
What travels further? Sound or light?
Light
What is ultrasound?
Sound between 20Hz and 20000Hz
Humans can’t hear it
Used in echolocation
What is the definition of ultrasound?
When sound waves reach a boundary between two media, part of the wave reflects back, part of it transmits through. The reflected parts are captured by a computer and an image can be generated
What is ultrasound used for?
Tumors
Deformed organs
Break up kidney stones
What are the 2 types of waves?
Mechanical waves
Electromagnetic waves
What are the principels of mechanical waves?
Either transverse or longitudinal
Disrupts the particles of the medium its travelling through
Transfer energy not particles
What are the principles of electromagnetic waves?
Transverse
Disturbtion of the electric and magnetic field
Electric and magnetic field changes
Carries energy
What is wave-particle duality?
Electromagnetic radiation exhibits both wave properties and particle properties at the same time
What are photons?
Discrete packets of energy
Elementary particle
Do not have mass
Called “quanta of energy”
Carries a certain amount of energy
travels at the speed of light
Explain the energy carried by a photon.
High frequency > short wavelength > more energy
What is the electromagnetic spectrum?
7 types of radiation
What are the 7 types of electromagnetic radiations?
Radio waves
Microwaves
Infrared
Visible light
Ultraviolet
X-rays
Gamma rays
