6. Waves Flashcards
What type of spectrum do electromagnetic waves form?
A continuous spectrum.
Order the types of electromagnetic radiation from lowest to highest frequency.
● Radio waves
● Microwaves
● Infrared
● Visible Light
● Ultraviolet
● X-rays
● Gamma Rays
How do the speeds of EM radiation differ in a vacuum and in air?
Electromagnetic waves all travel at the same speed in a vacuum and in air.
In which direction do waves refract when entering a denser medium?
● They bend towards the normal
● The angle of refraction is less than the angle of incidence
Where do gamma rays originate from?
They originate from changes in the nuclei of atoms.
What health effects can ultraviolet waves cause?
● They can cause the skin to age prematurely
● They can increase the risk of developing skin cancer
What health effects can X-rays and Gamma rays cause?
● They are ionising radiation so can cause mutations in genes
● They can lead to increased risk of developing various cancers
Give three practical uses for infrared radiation.
- Electrical heaters
- Cooking food
- Infrared cameras
Give two practical uses for microwave radiation.
- Satellite communications
- Cooking food
Give two practical uses for radio waves.
- Television transmission
- Radio transmission
What are the two types of waves?
- Transverse
- Longitudinal
What is a transverse wave?
A wave for which the oscillations are perpendicular to the direction of energy transfer.
What is a longitudinal wave?
A wave for which the oscillations are parallel to the direction of energy transfer.
Give two examples of transverse waves.
- Electromagnetic waves
- Seismic s-waves
Give two examples of longitudinal waves.
- Sound waves
- Seismic p-waves
What are the two parts of a longitudinal wave called?
Compressions and rarefactions.
What is a wave’s amplitude?
The maximum displacement of a point on a wave from its undisturbed position.
What is wavelength?
● The distance from a point on a wave to the same position on the adjacent wave
● Most commonly peak to peak or trough to trough
What is the frequency of a wave?
The number of waves that pass a given point each second.
What is the unit used for frequency?
Hertz, Hz
What is meant by a frequency of 200Hz?
200 waves pass a given point each second.
What is wave speed?
The speed at which the wave moves or at which energy is transferred through a medium.
What does a wave transfer?
Energy
State the equation used to calculate wave speed.
Wave Speed = Frequency x Wavelength
Speed (m/s), Frequency (Hz), Wavelength (m)
What word is used to describe when a wave bounces off a surface?
Reflection
