# 12.2 Boundary conditions  (Page 5/5)

 Page 5 / 5

## Superposition and interference

1. For each labelled point, indicate whether constructive or destructive interference takes place at that point.
2. A ride at the local amusement park is called "Standing on Standing Waves". Which position (a node or an antinode) on the ride would give the greatest thrill?
3. How many nodes and how many anti-nodes appear in the standing wave below?
4. For a standing wave on a string, you are given three statements:
1. you can have any $\lambda$ and any $f$ as long as the relationship, $v=\lambda ·f$ is satisfied.
2. only certain wavelengths and frequencies are allowed
3. the wave velocity is only dependent on the medium
Which of the statements are true:
1. A and C only
2. B and C only
3. A, B, and C
4. none of the above
5. Consider the diagram below of a standing wave on a string 9 m long that is tied at both ends. The wave velocity in the string is 16 m $·$ s ${}^{-1}$ . What is the wavelength?

## Summary

1. A wave is formed when a continuous number of pulses are transmitted through a medium.
2. A peak is the highest point a particle in the medium rises to.
3. A trough is the lowest point a particle in the medium sinks to.
4. In a transverse wave, the particles move perpendicular to the motion of the wave.
5. The amplitude is the maximum distance from equilibrium position to a peak (or trough), or the maximum displacement of a particle in a wave from its position of rest.
6. The wavelength ( $\lambda$ ) is the distance between any two adjacent points on a wave that are in phase. It is measured in metres.
7. The period ( $T$ ) of a wave is the time it takes a wavelength to pass a fixed point. It is measured in seconds (s).
8. The frequency ( $f$ ) of a wave is how many waves pass a point in a second. It is measured in hertz (Hz) or $s{}^{-1}$ .
9. Frequency: $f=\frac{1}{T}$
10. Period: $T=\frac{1}{f}$
11. Speed: $v=f\lambda$ or $v=\frac{\lambda }{T}$ .
12. When a wave is reflected from a fixed end, the resulting wave will move back through the medium, but will be inverted. When a wave is reflected from a free end, the waves are reflected, but not inverted.

## Exercises

1. A standing wave is formed when:
1. a wave refracts due to changes in the properties of the medium
2. a wave reflects off a canyon wall and is heard shortly after it is formed
3. a wave refracts and reflects due to changes in the medium
4. two identical waves moving different directions along the same medium interfere
2. How many nodes and anti-nodes are shown in the diagram?
3. Draw a transverse wave that is reflected from a fixed end.
4. Draw a transverse wave that is reflected from a free end.
5. A wave travels along a string at a speed of $1,5m·s{}^{-1}$ . If the frequency of the source of the wave is 7,5 Hz, calculate:
1. the wavelength of the wave
2. the period of the wave
6. Water waves crash against a seawall around the harbour. Eight waves hit the seawall in 5 s. The distance between successive troughs is 9 m. The height of the waveform trough to crest is 1,5 m.
1. How many complete waves are indicated in the sketch?
2. Write down the letters that indicate any TWO points that are:
1. in phase
2. out of phase
3. Represent ONE wavelength.
3. Calculate the amplitude of the wave.
4. Show that the period of the wave is 0,67 s.
5. Calculate the frequency of the waves.
6. Calculate the velocity of the waves.

how can chip be made from sand
is this allso about nanoscale material
Almas
are nano particles real
yeah
Joseph
Hello, if I study Physics teacher in bachelor, can I study Nanotechnology in master?
no can't
Lohitha
where is the latest information on a no technology how can I find it
William
currently
William
where we get a research paper on Nano chemistry....?
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
Ali
what are the products of Nano chemistry?
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
hey
Giriraj
Preparation and Applications of Nanomaterial for Drug Delivery
revolt
da
Application of nanotechnology in medicine
has a lot of application modern world
Kamaluddeen
yes
narayan
what is variations in raman spectra for nanomaterials
ya I also want to know the raman spectra
Bhagvanji
I only see partial conversation and what's the question here!
what about nanotechnology for water purification
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Got questions? Join the online conversation and get instant answers!