Waves Key Questions Flashcards
What is a transverse wave?
The vibrations/oscillations of the waves are
perpendicular to the direction of energy transfer.
What is a longitudinal wave?
The vibrations/oscillations of the waves are parallel to the direction of energy transfer.
Define amplitude
The maximum displacement of a point on a wave away
from its undisturbed position.
Define wavelength
The distance from a point on one wave to the equivalent
point on the adjacent wave.
What is equation linking time period and
frequency?
Time period= 1÷ frequency
What are the units for frequency?
Hz or Hertz
What is equation linking wave speed,
frequency and wavelength?
Wave speed = frequency × wavelength
Are electromagnetic waves transverse or
longitudinal?
Transverse
What do EM waves transfer?
Energy
Explain why EM waves are not mechanical waves.
They can travel through a vacuum.
What is the order of the electromagnetic waves from highest frequency to lowest frequency?
Gamma rays, X-rays, Ultraviolet, Visible light, Infrared, Microwaves, Radiowaves
What can occur when an EM wave meets a substance?(a,t,r,r)
Absorbed, transmitted, refracted and reflected
When does refraction happen?
A change in velocity
How can EM waves be produced?
Change inside an atom
How can radio waves be produced?
Oscillations in an electrical circuit
How can we detect radio waves?
They create an alternating current with the same frequency
What is Radiation dose?
a measure of the risk of harm from the body being exposed to radiation
Which EM waves are ionising?
X-rays and Gamma
What are the dangers of ultraviolet waves?
Can cause skin to age prematurely and increase the risk of skin cancer.
What are the dangers of X-rays and Gamma rays?
Can cause the mutation of genes and cancer
What can radio waves be used for?
Television and radio
What can microwaves be used for?
Satellite communications and cooking food
What can infrared be used for?
Electrical heaters, cooking food, infrared cameras
What can visible light be used for?
Fibre optic communciations
What can ultraviolet be used for?
Energy efficient lamps, sun tanning
What can gamma rays be used for?
Sterilising equipment, medical treatment
What can x-rays be used for?
Medical imaging and treatments
Why are X-rays used for medical imaging?
They pass through the flesh but not bone
Why are gamma rays used for treating cancer and sterilising medical equipment?
High doses kills cells and bacteria
What surfaces absorb radiation?
All surfaces, black is the best absorber
What surfaces emit radiation?
All surfaces, black is the best emitter
State how light waves travel
in straight lines
Which waves travel faster; light or sound?
light waves
What is an echo?
a reflection of a wave when it hits a boundary
Describe reflection off a plain surface (ai=ar)
the angle of incidence is equal to the angle of reflection
What is a luminous object?
an object that emits light
What is superposition? (2wici)
When two waves interact with each other they can either cancel each other out or make each other more intense
Define ‘medium’ (media is plural)
a substance e.g. water,air,glass
Which surfaces are the best reflectors?
silver shiny
