Waves Flashcards
What is the amplitude of a wave
The distance from the middle to the crest or trough
Frequency =
Number of waves per second
What is frequency measured in
Hertz
In a transverse wave the vibrations are…. To the direction of energy transfer
Perpendicular
In longitudinal waves the waves are …to the direction of energy transfer
Parallel
Wave speed=
Frequency x wavelength
In relflection the angle of incidence is= to what?
The angle of reflection
Where is an image formed in a mirror
Behind it
When constructing a diagram to show how images are formed in mirrors one of the ray arrows goes beyond the mirrow from where does this ray begin
The eye
Any lines going behind the mirror when drawing a diagram of reflection should be
Dotted
When does diffraction occur
When a wave passes though a gap or obstacle
The level of diffraction depends on what
The size of the gap releative to it’s wavelength
When does maximum diffraction take place
When the size of the gap is equal to the wavelength
Name the em waves in order
Radio Micro Infra red Visible Ultra violet X rays Gamma rays
Radio waves have the….wavelength
Biggest
Which rays have the shortest wavelength
Gamma rays
The higher the frequency the
Shorter the wavelength
Why doesn’t the receiver of radio waves need to be in line of sight
Because it can diffract
Why are microwaves used for satellite communication rather than radio waves
Because they can pass through the atmosphere where as radiowaves are reflected by it
How do satellites work
Signal sent from transmitter to space
Satellite picks up signal
The signal is retransmitted to a new place
The satellite on the ground picks up the signal
How do mobile phones work
They use microwaves to transmit to the nearest mast
Why do some people think using phones and living near a mast can cause Heath damage
Water absorbs microwaves and causing the water to heat up . The water in the cells can heat thus “cooking” the cells
How do remote controls work
They emit different patterns of infrared waves which send the command
Optical fibres can carry data… And …
Over long distances
Quickly
