Electromagnetic Waves Flashcards
Explain the hazards between gamma, x rays, ultraviolet
All can ionize atoms within body which can lead to cancer
What are some uses for gamma, xray and ultraviolet.
Gamma- sterilisation or radiotherapy
Xray- medial imaging
Ultraviolet- security or energy saving light bulbs
State the independent variable for the EM practical
Type of surface area
Describe how an electrical signal in a transmitter is sent to receiver.
Electrical input causes electrons to vibrate.
This leads to radio waves which travels between transmitter and receiver.
In receiving Antenna, radio waves forces electrons to vibrate
How are longitudinal waves different from transverse
Longitudinal, waves are parallel to direction of energy transfer. (Move side to side)
Transverse , waves are perpendicular to direction of energy transfer. (Move up and down)
State 2 control variables
Distance from heater to surface
The amount and type of wax used
What surface will the drawing pin fall from first?
Matt black surface as black surfaces absorb more infrared than lighter ones
What happens to white or silver surfaces.
Reflects infared
2 properties of transverse
Travel at speed of light
Travel through a vacuum
Properties of longitudinal waves
Requires a medium like water or air to travel
Explain why the temperature of water in flasks increases then becomes constant.
Flask absorbs infared radiation
Energy is transferred to surroundings
Initially, rate of infared absorption is greater than energy transfer
Energy transfer to surroundings increases as temperature of flask increases
Eventually, rate of energy transfer is equal to rate of absorption so line flattens
Investigate how amount of IR absorbed by a surface depends on the surface.
Fill Leslie cube with hot water and place on heat proof mat
Place lid on
Use detector to measure amount of IR emitted from each surface.
Ensure it’s the same distance
allow time for each reading for the detector to settle
