#### Waves and Cosmology - AQA GCE Physics Revision Notes

Matter waves * As waves can behave as a stream of particles, particles can also behave as a wave De Broglie wavelength: λ = where mv is the momentum of the particle * Diffraction rings are where electron waves interfere constructively to produce a maximum - energy gained by electron is equal to the kinetic energy of the electron. Here, electrons are accelerated by a voltage of 2000 V; 2000 x (1.6 x 10-19) = x (9.11 x 10-31) x v2 Mass of electron = 9.11 x 10-31 3.2 x 10-16 = x (9.11 x 10-31) x v2 v2 = 7.025247 x 1014 v = 2.65 x 107 ms-1 So the momentum of electron: (9.11 x 10-31) x (2.7 x 107) = 2.5 x 10-23 kgm/s The de Broglie wavelength: λ = = = 2.6 x 10-11 m * If the accelerating voltage increases, energy and momentum of the electron would decrease the wavelength. Shorter wavelength blue light falling on diffraction grating produced fringes that are closer together than longer wavelengths (red light). * Resolving power is the wavelength of radiation used to determine the smallest object we are able to detect with it. The smaller the wavelength, the better the resolution. I.e. Resolution of visible object is limited by its wavelength of 5 x 10-7 m. In electron microscope, electrons are accelerated through 30000 V have wavelength of about 10-12 m, and so can produce images of object as small as a nanometre. When

• Word count: 6842
• Level: AS and A Level
• Subject: Science

#### An experiment to investigate and determine how rubber behaves when tension forces are applied to it.

Physics AT1 An experiment to investigate and determine how rubber behaves when tension forces are applied to it By Jess McFarlane 11WM Aim The initial aim of my experiment is to investigate how rubber behaves when tension forces are applied to it. I also intend to figure out why this happens so that the data that I am provided with will help me to analyse what I plan to write about during this set coursework. For the actual experiment I will be using a rubber band, as this is an easier and less complex way of carrying out the investigation. Introduction When a sample of material in the form of rubber, such as in this case, is pulled so as to apply a tension force, the sample would become longer in size. And the difference between the new length of the sample and its existing length, when there was no tension applied to it, this is called the extension of the particular sample. Tension is a force that is applied to an object of material that is able to change in size, for example, these types of materials could be used, rope, springs, rods, wires and in this particular case rubber. Tension is the name given to a force, which acts through a stretched sample or object e.g. when a pulling force is applied at each end of the rope, it is said to be under tension. Extension occurs in this experiment as well. A definition of extension is when an object such as rubber is

• Word count: 5019
• Level: AS and A Level
• Subject: Science

#### Earthquake Simulation Program.

Earthquake Simulation Program Background What is an earthquake? The definition of an earthquake is a violent vibration of the Earth that is caused by the sudden release of energy, usually as a result of faulting, which involves the displacement of rocks along fractures. They occur when rocks have been placed under huge amounts of pressure, for example if you take the rocks in the lithosphere, if the pressure increases very slowly, they will deform slightly. However, the problem is that all solids have a limit and continuous pressure will result in the shattering or fracturing of them. This is because rocks are brittle substances and will ultimately break under pressure, without warning, hence a sudden fracture, which is otherwise known as faulting. If a rock takes a long time to deform then it will take a long time for an earthquake to occur. After an earthquake has occurred, the fault makes adjustments, which are known as aftershocks. These cause considerable damages to the buildings already weakened by the earthquake itself. Aftershocks can be persistent from a few days up to a few months after the earthquake has occurred, depending on the size of the earthquake. However, in order to understand how they occur, we need to address the plate tectonic theory. This theory suggests that the Earth be broken up into several plates, which are thick slabs of rock.

• Word count: 4970
• Level: AS and A Level
• Subject: Science

#### The aim of this investigation is to examine the effect on the spring constant placing 2 identical springs in parallel and series combination has and how the resultant spring constants of the parallel and series spring sets compare.

Spring Constant of Springs in Series and Parallel AS Physics Coursework By Malcolm Davis Planning The aim of this investigation is to examine the effect on the spring constant placing 2 identical springs in parallel and series combination has and how the resultant spring constants of the parallel and series spring sets compare to that of a lone spring with identical spring constant. Hypothesis Hooke's Law states that "The magnitude of the spring constant (k) is equal to the stretching force applied (F) divided by the resultant extension (x)", it should be possible to determine a spring constant for each spring set. Due to existing knowledge of springs I propose that the series spring set will have a lower spring constant (and hence due to Hooke's Law display a greater extension) than the parallel spring set. Also, as Hooke's Law is a linear function, the spring constant of the series spring set should be exactly half that of a single spring, whereas the spring constant of the parallel set should be exactly double that of the single spring. This also means that if the resulting extension or spring length of the spring sets are graphed along a y axis with the increasing force mapped to the x axis (so that the results can be displayed in a traditional scientific graph fashion), the gradient will be the inverse of the spring constant. This hypothesis is backed up by many

• Word count: 4714
• Level: AS and A Level
• Subject: Science

#### An Experiment To Examine the Effect of Springs In Parallel

AN EXPERIMENT TO EXAMINE THE EFFECT OF SPRINGS IN PARALLEL I am going to set up an experiment to see what happens to the extension of springs that are all the same size and material in parallel. I will use identical springs and in parallel they will look like this: I am going to add on springs in parallel (see above) to a fixed load and examine what effect this has to the extension of the springs. The load that will be kept the same throughout the experiment will also be kept at mid-point of all springs. EXTENSION will be the increase in length compared to the original length with no force applied. The extensions will tell me what is happening to the length of the springs when there are more springs to support a fixed load. PREDICTION I predict that as I add on springs in parallel to a fixed load like so: the extension of the springs will decrease. A metal spring is made up of molecules. Between these molecules are attractive forces like so: When we add a load (N) to the spring the length of the spring increases, (it stretches) and therefore becomes weaker. The force pulling the spring is pulling on each molecule inside it. The force, acting on the molecules, makes them pull away from each other. When this happens the resultant force decreases and the spring extends. (Found information for last sentence in a revision text book) When we add on more springs, in

• Word count: 4560
• Level: AS and A Level
• Subject: Science

#### What factors affect the period of a Baby Bouncer?

OBJECTIVE: To examine what factors determine the period of each oscillation: * How does the Bouncer's performance depend on the size of the baby? * What effect has the sort of support on the bounce? DIAGRAMATIC REPRESENTATION OF THE SYSTEM: The oscillation pattern of such a mass-spring system can be characterised as a harmonic oscillator. CONSIDERATION OF THE THINGS WHICH CAN BE CHANGED IN SUCH AN OSCILLATING SYSTEM: The things which can be changed in such a system that will impact the period of each oscillation are: * The mass of the baby (load) * The material which the spring support is composed of * The length of the spring support * The stiffness of the spring support * The strength of the spring support * The thickness of the spring support * The amplitude [Whether the baby bounces up and down in a vertical manner or whether he or she imparts a rotational motion or forward/backward motion will have some impact on the oscillation period]. The above points are called variables and experiments could be conducted to investigate the effect of changes in each variable (whether absolute, such as changing the material of the spring support, or progressive, such as the addition of progressively large masses to the spring support to determine its elasticity.) In order to perform each series of experiments it would be necessary to keep all of the other components

• Word count: 4474
• Level: AS and A Level
• Subject: Science

#### I intend to investigate whether any correlation exists between the wavelength of light exerted upon a small solar cell impacts its rate of increase to response time

Amrik SadhraQOMFirst Report Solar Cell Response Times Quality Of Measurement Introduction For my quality of measurement coursework, I intend to investigate whether any correlation exists between the wavelength of light exerted upon a small solar cell impacts its rate of increase to ‘response time’ in any way. Response time in this scenario will be defined as the time required for the cell to reach its nominal voltage from 0v. The rate will be a measure of the response time divided by the voltage increase (measure of gradient). This will require the precise control of a number of variables; the largest being the co-ordination of light source start up and the voltage logging from the solar cell. The practical applications of a wavelengths affect on solar cells are limited. In the case of data transfer, much more tailored methods exist. However, a hobbyist could use the information obtained here to build a very cheap receiver and transceiver for the transmission of data, given the low costs of solar cells and their abundance in consumable electronics (calculators, garden lights etc.). The cells response time will dictate the rate of data transfer, as bits can be signified by the rise and fall of the cells voltage. The wavelength of light pulsed to generate these bits will need to extract the highest transfer speeds possible by coaxing a smaller response time from the

• Word count: 4341
• Level: AS and A Level
• Subject: Science

#### Determine the value of 'g', where 'g' is the acceleration due to gravity.

PHYSICS COURSEWORK AIM The aim of this investigation is to determine the value of 'g', where 'g' is the acceleration due to gravity. The value will be determined using the simple harmonic motion of a mass spring system. PREDICTION The aim of this investigation is to determine the value of gravity. I believe that my value of 'g' will be around 9.81ms-2 because the published value of gravity is 9.81ms-2 for reference check (http://www.egglescliffe.org.uk/physics/gravitation/bifilar/bif.html). This value was first discovered by a very famous scientist Isaac Newton. As we are talking about acceleration, we can consider formula's associated with it:- We know (if signs are ignored) * a- acceleration * - constant * - displacement * m- is the mass of the system The force causing the acceleration (a) at displacement () is ma, therefore ma/is force per unit displacement. Hence:- The period T of the simple harmonic motion is given by:- AND This shows that T increases if:- * the mass of the oscillating system increases * the force per unit displacement decreases HOOKE'S LAW Hooke's law states that the extension of a spring (or other stretch object) is directly proportional to the force acting on it. This law is only true if the elastic limit of the object has not been reached. * F- force acting on the spring * e- extension of a spring due to the force

• Word count: 4247
• Level: AS and A Level
• Subject: Science

#### Damping of an mechanic oscillator.

Damping of an mechanic oscillator Introduction An object oscillates when it moves back and forth repeatedly, on either side of some fixed position (centre). If we stop it from oscillating, it returns to it original position. This sort object is called an oscillator. Vibrations exist in two types: free and forced. An object experiences forced oscillations when its frequency (number of vibrations per second) is not its natural frequency of vibrations. If its frequency of vibrations is its natural one, it will then experience free vibrations. When the amplitude of oscillations of an object remains the same as it goes back and forth, the oscillations of that object are harmonic. And if the amplitude decreases instead, it is said that oscillations are damped and the phenomenon is called damping. In this experiment, I will study what might affect damping and then measure it. Study of some oscillators . A mass-spring system I set using a tall stand, springs, a hanger and three 50gram masses, a system that I got to oscillate. I hold and displaced slightly the masses vertically downwards making sure I don't deform any of the springs and released it. As a let it oscillate for a few minutes, I noticed that the displacement (from the originial position) of the oscillations was deceasing for the system of masses tended to return back to its original position. The room in which I

• Word count: 4069
• Level: AS and A Level
• Subject: Science

#### Stretching Springs/Hookes Law.

Mustafa Rafik 0.7Api Science coursework Title: Stretching Springs/Hookes Law Mr Bhatwadekar Scientific knowledge A force is able to change the shape of an object, the more the strength and force you apply, the more the shape of the object will change because the particles of the object are being moved therefore it will change the shape of the object because of the particles being pushed for e.g. A force is also able to change the motion of the object. The force, which is applied to the object, makes the object stay in that shape which is the cause of the force hitting the object and making it change, this will not go back to its original shape like shown in number 2, this is because the particles have been hit so hard that the attraction of the particles which makes them go back to its original shape have been damaged so it will then go into another shape. Elastic material This is a material that will stretch and go back to normal, its original shape. Elastics behavior is the ability of a solid to regain its shape when the external forces are removed. What is Hookes Law? Hokes Law is a rule for a spring, 'For a spring-that for a helical spring or other elastic material the extension is directly proportional to the applied force provided the elastic limit is not exceeded' This means that the extension is directly proportional to its force until its elastic

• Word count: 3692
• Level: AS and A Level
• Subject: Science