P2- Topic 6 - Waves 2022 Flashcards
What are the two types of waves?
- Transverse
2. Longitudinal
What is a transverse wave and example ? 3
A wave for which the oscillations are
perpendicular to the direction of energy
transfer
Electromagnetic waves
Seismic s-waves
What is a longitudinal wave? and example 3
A wave for which the oscillations are
parallel to the direction of energy
transfer
Sound waves
Seismic p-waves
Why is the wave and not
the water or air itself that travels.
3
all waves trasnsfer energy from one place to another
rippels transfer kinetic energy
sound waves transfer sound energy
What are the two parts of a longitudinal wave called?
Compressions and rarefactions
What is a wave’s amplitude?
distance from equilibrium line to the maximum displacement (crest or trough) .
What is wavelength?2
distance between the same points on two consecutive waves
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
1Hz= 1 wave per second
What is the unit used for frequency?
Hertz, Hz
What is wave speed?
the speed at which the energy is transferred (or
the wave moves) through the medium.
how to calculate the period of one wave?
period = 1÷frequency
T =1÷f
Period(s) frequency(Hz)
State the equation used to calculate wave speed.
Give appropriate units
2
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
describe a method to measure the speed of sound waves in
air 3
Make a noise at ~50m from a solid wall, and record time for the echo to be heard,
then use speed = distance/time
Have two microphones connected to a datalogger at a large distance apart, and
record the time difference between a sound passing one to the other – then use
speed = distance/time
describe a method to measure the speed of ripples on a water
surface 3
Use a stroboscope, which has the same frequency as the water waves
measure distance between the ‘fixed’ ripples and use
𝑣 = 𝑓/⁁
Move a pencil along the paper at the same speed as a wavefront, and measure the time taken to draw this line – then use speed = distance/
What is a Reflected ray on different surfaces
Waves will reflect off a flat surface
- The smoother the surface, the stronger the reflected wave is
- Rough surfaces scatter the light in all directions, so they appear
matt and not reflective.
What is a transmission wave on different materials
Waves will pass through a transparent material
- The more transparent, the more light will pass through the material
- It can still refract, but the process of passing through the material and still emerging is
transmissio
What is absorption of a wave on different materials 2
waves are absorbped by the material the wave is trying to get into
tramsfers the energy to the materials energy strores
what does the angle of incidence equal
the angle of reflection
What is the frequency range of human hearing?
Higher
20 Hz - 20kHz
what is the effect on sound waves on an eardrrum 3
sound waves hit the
eardrum
compression forces ear inward, rarefraction outward by pressure
sound waves cause the ear drum and other parts of the inner ear to vibrate
causing sound
why such processes only work over a limited
frequency range and the relevance of this to human hearing. 2
works over limited frequency range as the normal human hearing is 20Hz to 20kHz
frequenecies outside this range may not be able to cause the eardrum to vibrate
How do sound waves travel through a solid?
The particles in the solid vibrate and
transfer kinetic energy through the
material.
causes of limitations to the ear 4
cochlea= hairs attuned to the higher frequencies die or get damaged.
constant loud noise damaging these hairs over the years
changes in the inner ear as you grow older
o Smoking, chemotherapy, diabetes
o So higher frequencies cannot be heard as we get older
What are ultrasound waves?
Waves which have a frequency higher
than the upper limit of human hearing
(20kHz)
Give an example use for ultrasound waves?2
Medical or industrial imaging.
pregnancy scan
What natural event causes seismic waves to be produced? What types are
produced? 3
● Earthquakes
● They produce both P-waves and
S-waves
State a difference between the mediums that P-waves and S-waves can travel through. 2
● P-waves travel through both solids and liquids
● S-waves only travel through solids
(not liquids)
What technique is used to detect objects in deep water and measure water depth? 4
● Echo sounding
● High frequency sound waves are emitted,
reflected and detected
● Time difference between emission and detection,
alongside wave speed, are used to calculate
distances
What type of spectrum do
electromagnetic waves form?
A continuous spectrum
Order the types of electromagnetic radiation from lowest to highest frequency.
7
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.
