P1.5 Flashcards
Describe the oscillations in a transverse wave
They are perpendicular to the direction of energy transfer
Describe the oscillations in a longitudinal wave
They are parallel to the direction of energy transfer
Are electromagnetic waves transverse or longitudinal?
Transverse
Are sound waves transverse or longitudinal?
Longitudinal
Are mechanical waves transverse or longitudinal?
Both (could be transverse OR longitudinal)
TRICKED YOU LMAO
Can all electromagnetic waves travel through a vacuum (space)?
Yes
What do all electromagnetic waves have in common?
They are all transverse
They all travel through a vacuum (space) at the same speed
What is the electromagnetic spectrum?
Waves which cover a continuous range of wavelengths
Name all the waves in the electromagnetic spectrum
Radio Microwave Infrared Visible Ultraviolet X-ray Gamma ray
Which electromagnetic wave has the longest wavelength?
Radio waves
Which electromagnetic wave has the shortest wavelength?
Gamma rays
What is the range of wavelengths in the electromagnetic spectrum?
About 10 ^–15 metres to more than 10 ^4 metres
Which electromagnetic wave has the highest frequency?
Gamma rays
Which electromagnetic wave has the lowest frequency?
Radio waves
What is the range of frequencies in the electromagnetic spectrum?
About 10^4 Hz to 10^20 Hz
Which electromagnetic wave has the most energy?
Gamma rays
Which electromagnetic wave has the least energy?
Radio waves
What do longitudinal waves show?
Areas of compression and areas of rarefaction
What is compression?
Where particles are close together (increasing density in that area)
What is rarefaction?
Areas where the particles are more spread out (less dense)
How can waves be affected?
By reflection, refraction and diffraction
What is refraction?
When waves change speed if they have passed a boundary between mediums of different densities, causing the direction of the wave to change
When are waves not refracted?
When they are travelling along the normal line
What do waves transfer?
Energy
What is diffraction?
When waves pass a gap and become more spread out as a result
What is reflection?
When a wave ‘bounces off’ a surface
What is amplitude?
The maximum disturbance from the undisturbed position of the wave
(Distance from the top of the wave to the line running through the middle)
When is diffraction most significant?
When the wavelength of the wave is the same size as the gap/obstacle
What is wavelength?
The distance from one point on the wave to the same point on the next wave (e.g. trough to trough or crest to crest)
What is frequency?
How many waves are produced per second
Give the equation which links frequency, wavelength and wave speed
Wave speed= frequency x wavelength
What unit is frequency given in?
Hertz (Hz)
Which types of electromagnetic waves are used for communication?
Radio waves
Microwaves
Infrared radiation
Visible light
In what situations would radio waves be used for communication?
In television and radio
Diffraction effects are used
In what situations would microwaves be used for communication?
Mobile phones
Satellite television
In what situations would infrared radiation be used for communication?
Remote controls
In what situations would visible light be used for communication?
In photography
What is the normal?
A line perpendicular (at 90°) to the surface at the point of incidence
What is the relationship between the angle of incidence and the angle of reflection?
These angles are equal
What are the two types of wave?
Transverse
Longitudinal
What is the nature of an image produced in a plane mirror?
Virtual
Upright
Laterally inverted
What type of wave is a sound wave?
Longitudinal
How are sound waves created?
By vibrations in a medium
What is the pitch of a sound determined by?
The frequency of the sound waves
What is the loudness of a sound determined by?
It he amplitude of the sound waves
What are echoes?
Reflections of sounds
What is the Doppler effect?
When the distance between a wave source and a person changes, which causes a change in the observed wavelength and frequency
What could the wave source (in the Doppler effect) be?
Light waves
Sound waves
Microwaves
What happens to the observed wavelength and frequency when the wave source moves away from the observer?
Wavelength increases
Frequency decreases
What is red-shift?
The effect observed that the further away galaxies are, the faster they are moving and the greater the increase in wavelength
What does red-shift show?
That the universe is expanding
What theory does red-shift support?
The Big Bang theory
What is the Big Bang theory?
The idea that the universe began from a small initial point
What does CMBR stand for?
Cosmic microwave background radiation
What is CMBR?
A type of radiation filling the universe, which has developed from radiation present after the universe first began
Which theory is the only one that can explain CMBR?
The Big Bang theory
What happens to the observed wavelength and frequency when the wave source moves towards the observer?
Wavelength decreases
Frequency increases
