Table Tennis Ball.

Physics Coursework 2004 Table Tennis Ball Experiment Prediction The table tennis ball will bounce lower as the height that it is dropped from decreases. This is because as the ball gets lower there is a lesser amount of force pushing the ball downwards therefore giving less velocity for it to rebound up into the air. This means that when it hits the ground the atoms push each other away forcing the ball to bounce higher. The graph begins to level out because parts of the ball begin to melt at certain temperatures as the atoms get more energy and break their bonds turning the ball into a liquid. A theory, which links into this experiment, is the kinetic theory. This is because the kinetic theory deals with atoms vibrating as they receive more energy and in doing so breaking their bonds. This is linked to this experiment because as the squash ball's atoms get more energy and vibrate more before breaking their bonds to become a liquid. Method We set up the apparatus as shown in the above diagram. We then dropped it from 100 cm high and measured the bounce. We then repeated the experiment 9 times, each time dropping it 10cm lower. To keep the experiment fair the only variable, which we changed, was the height. We used the same ball through out the experiment and checked the ruler had not moved. My range of results was very wide in order to get an accurate set of results.

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  • Level: University Degree
  • Subject: Physical Sciences
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One Hundred Years of Electrons.

ONE HUNDRED YEARS OF ELECTRONS. On April 30, 1897, at a meeting of the Royal Institution in London, physicist Joseph John (J.J.) Thomson declared that cathode rays lighting up a fluorescent screen were made of negatively charged particles. Thomson boldly proclaimed that these particles--which we now know as electrons--could be found in all atoms. The term "electron" as it applied to electricity actually came about in 1891 to describe the unit of electric charge in a chemical reaction. The electron was the first known subatomic corpsucle and its discovery marks the advent of particle physics. Michael Riordan (editor of SLAC Beamline, whose Spring 1997 issue is devoted to the electron centennial) refers to the electron as a truly "industrial strength" particle, since it is the workhorse of electronics, including television, telephones, and personal computers. (Many of these devices organize electrons inside transistors which were themselves developed exactly half a century ago.) Labor saving devices aside, electrons are of course the outer constitutents of all atoms and the principal currency of exchange in all chemical reactions. Faraday's Laws of Electrolysis When an electric current is made to pass through a cell, the current may cause chemical reactions to occur at its electrodes. This process is called electrolysis and the cell in which it occurs is called an

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  • Subject: Physical Sciences
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SELECTED PROBLEMS OF MODERN PHYSICS I. THE PHOTOELECTRIC EFFECT

SELECTED PROBLEMS OF MODERN PHYSICS I. THE PHOTOELECTRIC EFFECT . How to demonstrate experimentally that photoelectrons are emitted from an illuminated metallic surface? Ultraviolet light cause emission of free negative charges (photoelectrons) from metal surfaces. We can show this phenomena in a simple experiment. A freshly polished plate of zinc connected with an electroscope is charged negatively. When the plate is illuminated by visible light only, nothing happens (the charge on its surface is constant). But when we illuminate the plate using ultraviolet light, a discharge is observed --> the leafs of the electroscope slowly fall. This is a result of electron emission from the zinc plate. What is important, we see that in case of zinc, the photoelectric effect takes place only when we replace the visible light with ultraviolet, which has a higher light-wave frequency. 2. Explain how the magnitude of photocurrent depends on light intensity. The magnitude of this photocurrent increases in proportion to light intensity.(fig.5.2) But increasing the intensity of light increases the number of photoelectrons, NOT their velocity (so increasing magnitude means growing number of photoelectrons) 3. Explain the dependence between photocurrent and the potential difference existing between a cathode and an anode. When the positive potential difference increases, the

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  • Subject: Physical Sciences
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Resistor and Capacitor Networks.

Daniel Wybrow Resistor/Capacitor Networks Abstract Resistor/capacitor circuits, and High and Low Pass filters are investigated and certain theories validated using experimental techniques as well as theoretical solutions. Measurements are recorded and tabulated, and also where necessary results are shown graphically. Contents Contents...................................................................................1 Equipment List...........................................................................2 Introduction...............................................................................2 Theory Experiment P-IE-R-1 (Ohm's Law)...................................................2 Experiment P-IE-R-2 (Resistor Networks)...........................................2 Experiment P-IE-R-3 (Kirchoff's Laws and Thevenin Resistor Networks)... 3 Experiment P-IE-R-4 (The Wheatstone Bridge)....................................5 Procedure Experiment P-IE-R-1..................................................................6 Experiment P-IE-R-2...................................................................6 Experiment P-IE-R-3 (Kirchoff's Laws).............................................7 Experiment P-IE-R-3 (Thevenin Equivalent Circuit)..............................8 Experiment P-IE-R-4...................................................................8

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The discovery of the elecron, proton and neutron

THE DISCOVERY OF THE ELECTRON, PROTON AND NEUTRON For thousands of years it was thought that the atom was the basic unit of matter, and more importantly the smallest unit of a chemical element. The idea of the atom came from Greek Philosophers and was derived from the Greek word atomos, meaning indivisible. Through experimentation and scientific theories during the 19th Century it was found that the atom had an internal structure and was therefore made up of other, smaller particles. We now know that the atom is made up of three fundamental particles; the electron, proton and neutron, which, in themselves are made up of even smaller particles, however the discovery of these three particles are at the beginning of modern science and is the subject of this essay. Until 1932, the atom was known to consist of a positively charged nucleus surrounded by enough negatively charged electrons to make the atom electrically neutral. Most of the atom was empty space, with its mass concentrated in a tiny nucleus. The nucleus was thought to contain both protons and electrons. The first subatomic particle to be discovered was the electron; the Irish physicist G. J. Stoney first used the name 'electron' for a unit of negative electricity in 1891. This was actually identified in 1897 by Joseph J. Thomson, however it can be said that the beginnings of the discovery of the electron started in

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EVIDENCE FOR SUBSHELLS We know already that shells contain a certain number of electrons.

EVIDENCE FOR SUBSHELLS We know already that shells contain a certain number of electrons. Each shell can hold up to a certain number of electrons and this will depend on where the shell is. For instance, the 1st shell can hold up to a maximum of 2 electrons, whereas the 2nd shell can hold up to 8 electrons, the 3rd can also hold up to 8 electrons and so on. We have also studied ionisation energies, which is the minimum amount of energy required to remove one mole of electrons from one mole of gaseous atoms to form one mole of uni-positive ions at 298k and 1 atmospheric pressure. In simpler terms it is the energy required to remove an electron from a shell. The energy required to remove them are dependant on 3 factors. - distance from nucleus - effective nuclear charge - shielding from other electrons When we plot the ionisation energy for the first 20 elements on a graph, it looks like the one shown below: From looking at the graph we can see that there is a drop from neon, which has a full outer shell to sodium which has one electron in its outer shell. The only reason for this drop would be that the effect nuclear charge has dropped. The ENC has dropped, although the nuclear charge has increased, because the new electron must have joined a new shell, and is thus further away from the nucleus as well as experiencing more shielding. This is why less energy is required

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  • Subject: Physical Sciences
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Investigation into the relationship between the length of a wire and the resistance

Investigation into the relationship between the length of a wire and the resistance Plan Introduction A metal conductor consists of atoms surrounded by a 'sea' of electrons; each atom donates electrons to the 'sea'. The electrons are always moving, but if there is no potential difference applied to either end, they move randomly. When a P.D. is applied the movement of the electrons is influenced and there is a net movement in a particular direction. In doing so they lose energy by colliding with atoms; the atoms gain energy and vibrate more, decreasing the chance of an electron passing without colliding. Preliminary Work We measured the resistance of 32 and 40 standard wire gauge at 10cm intervals between 0 - 30cm. Thickness of wire/ Standard Wire Gauge Length/ Cm Resistance/ ? Resistance minus probes/ ? 32 0 0.1 0.0 0 1.3 1.2 20 2.2 2.1 30 4.1 3.0 40 0 0.1 0.0 0 5.1 5.0 20 9.1 9.0 30 2.7 2.6 The results show resistance increasing as wire length increases resistance increases. Hypothesis I therefore predict that as the wire length increases so will the resistance, as the electrons will have to pass more atoms increasing the chance of a collision and slowing the electrons down. Also as the thickness of wire increases the resistance will decrease, as there will be more electrons so the chance of an electron not colliding increases. This

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  • Level: University Degree
  • Subject: Physical Sciences
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The three different crystallographic planes shown are for a unit cell of a hypothetical metal.

Andy Somody 97300-6222 ENSC 330 Assignment #4 ). a). The three different crystallographic planes shown are for a unit cell of a hypothetical metal. I have completed this question based on the assumption that each of the planes is rectangular. Therefore, the angles between each of edges of the planes must equal 90o. Each of the plane dimensions must completely be enclosed by the boundaries of the unit cell of the metal. Even though there are infinite parallel planes having Miller indices equivalent to those of the given planes, these are not enclosed by the unit cell of our metal. Thus, these equivalent planes do not need to be considered to determine the geometry, crystal system and crystal structure of our unit cell. Although we are given the edge lengths of the three crystallographic planes, this gives no information about the orientation of those edges. Therefore, since each plane is rectangular, there are two possible orientations for each plane. The correct orientation must allow the dimensions of all three planes to be correlated with one another. An initial diagram of the three planes of the unit cell is shown below: We can see from the above figure that one edge of the (001) plane must be equal in length to one edge of the (101) plane. There is only one possible orientation of the two planes that can produce this condition - the alignment of the 0.40 nm edge of

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  • Subject: Physical Sciences
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Formulation practical - Suspensions.

28th November 2003 Formulation practical - Suspensions Introduction A suspension is a coarse dispersion in which insoluble solid particles are dispersed in a liquid medium. Particle diameter is generally greater than 0.1µm. The essential point is that a drug prepared as a suspension will be in a solid form even though the dosage form as a whole is liquid. Suspensions are a widely used type of dosage form, for oral, inhalation, topical, ocular and, in some cases, parental administration. Drugs are formulated as suspensions because of their poor solubility, ease of swallowing and flexibility of administered dose. They have an increased chemical stability and a less noticeable taste as compared to a solution formulation. The limitation of formulating a drug as a suspension is that it needs to be shaken prior to measuring the dose, to re-suspend the suspension to gain an accurate dose. Over time, the solid particles tend to settle; the rate of sedimentation (v) is given by Stoke's Law: v = 2gr2 (?d - ?c) 9? where: g = acceleration due to gravity r = radius of the particle ?d = density of the disperse phase ?c = density of the continuous phase ? = viscosity of the continuous phase Rate of sedimentation can be decreased by reducing particle size, reducing the density difference or by increasing the viscosity of the dispersed phase. Reducing the size of the suspended

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The objective of this laboratory was to measure the speed at which sound was traveling through the air, using the resonance of longitudinal waves.

Experiment 13: Determining the Speed of Sound Samir Shuman April 29, 2011 Physics 111-C21 Objective: The objective of this laboratory was to measure the speed at which sound was traveling through the air, using the resonance of longitudinal waves. Equipment used: - Tall glass of water - PVC pipe, 10 in - Tape measure, 3 m - Mercury thermometer - Tuning fork, 384 Hz - Marker pencil - Block of wood Data: Data Table 1 Tuning fork frequency (Hz) Length, L Water level to top of tube (m) d= diameter of tube (m) ?= 4(L + 0.3d) (m) Experimental v=f? (m/s) Room Temperature (°C) 384 0.218 0.020 0.896 344.064 24 Calculations: In order to find the value of ? (the wavelength), I used the following equation: ?= 4(L + 0.3d) I then plugged the values from Data Table 1 in to find the sound wavelength. ?= 4 (0.218 m + 0.3 * 0.020 m) ?= 4(0.218 m + 0.006 m) ?= 4(0.224 m) ?= 0.896 m In order to find the experimental value of v (speed of sound), I used the following equation: v=f? I found ? previously by using the formula ?= 4(L + 0.3d). The value of f (the frequency of the tuning fork) was found written on the side the tuning fork. I then used the equation to find the speed of sound. v=f? v= 384 Hz * .896 m v= 344.064 m/s In order to find the actual speed of sound, I used the following equation (where Tc= room temperature in

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  • Level: University Degree
  • Subject: Physical Sciences
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