Physics - Waves Flashcards
In a transverse wave, are the vibrations perpendicular to the direction of energy or parallel to the direction of energy?
Perpendicular
In a longitudinal wave, are the vibrations perpendicular to the direction of energy or parallel to the direction of energy?
Parallel
What is an example of a transverse wave?
Water waves and light waves
What is an example of a longitudinal wave?
Sound waves
What is the frequency of a wave?
The number of waves which pass a given point every second
What is the equation for the time period?
time period (s) = 1 ÷ frequency (Hz)
What is the wave speed?
How quickly energy is transferred through a medium (how quickly the wave travels)
What is the equation for wave speed?
wave speed (m/s) = frequency (Hz) x wavelength (m)
What is the equation for speed?
speed = distance ÷ time
What determines the speed sound waves can travel through a medium?
The density of the medium (material)
Do sound waves travel faster through a solid or liquid?
Solid because the spaces between the particles are smaller. This means the vibrations and energy can be passed along the particles more quickly. In a gas, the transmission of sound is even slower as the space between the particles is greater.
What is the speed of sound in air?
300m/s
How do you measure a wavelength in the ripple tank required practical?
Use a meter rule and make an estimate quickly. You could use a stroboscope and freeze the waves to make this measurement more easily. Record 10 and calculate the mean for a more accurate recording.
What causes seismic waves?
Volcanoes, earthquakes and explosions
What are ultrasound waves?
Sound waves that have a higher frequency than the range which is detectable by the human ear
What is ultrasound used for?
Medical and industrial imaging for example in hospitals to take pictures of babies in the womb to check they’re healthy
Do electromagnetic waves transfer energy as transverse or longitudinal waves?
Transverse waves
What are electromagnetic waves grouped by in the electromagnetic spectrum?
Frequency
Which type of wave has the lowest frequency?
Radio waves
Which type of wave has the highest frequency?
Gamma rays
What’s a use for radio waves?
Communication via television and radio and satellite communications
What’s a use for microwaves?
Communications including satellite communications and cooking food
What’s a use for infrared waves?
Short-range communications (remote controls), electrical heaters, cooking food, optical fibres, security systems and thermal imaging cameras
What’s a use for visible light waves?
Used for lighting, photography and fibre optics.
What’s a use for ultraviolet waves?
Sterilising water and killing bacteria. Detecting forged bank notes
What’s a use for X-rays?
Medical imaging and airport security scanners
What’s a use for gamma rays?
Sterilising medical equipment or food and treatment for some cancers
What can high exposure to ultraviolet rays lead to?
Skin tanning and can lead to burns or skin cancer
What can high exposure to gamma rays lead to?
Gene mutation and cancer
Which wave has the shortest wavelength?
Gamma rays
Which wave has the longest wavelength?
Radio waves
How can you remember the order of the electromagnetic spectrum? (phrase)
Roman men invented very unusual X-ray guns
or
Grandma’s xylophones usually vomit in my room
What is the equation for frequency?
frequency (Hz) = 1 ÷ time period (s)
Name 2 examples of a mechanical wave
Sound waves (air)
or
Water/sea waves
or
Earthquakes
Name 2 examples of an electromagnetic wave
Colours (e.g. red/blue)
or
Microwaves
or
5G (phone signal)
Do transverse waves go up and down or side to side?
Up and down
Do longitudinal waves go up and down or side to side?
Side to side
What is the wave speed (m/s) if the frequency is 8.4Hz and the wavelength is 380cm?
8.4 x 3.8 = 31.92 m/s
