Experiment: Decay of Charge in a Capacitor
Physics(AL) TAS Laboratory Report Experiment: Decay of Charge in a Capacitor Content A. Objectives B. Theories and Hypothesis C. Experimental Design D. Results and Data Evaluation E. Error Analysis F. Summary and Conclusions G. Possible Improvements A. Objectives The objective is to investigate the decay of charge in a capacitor when it discharges through a constant resistance. The discharge processes of two identical capacitors connected in series or parallel are also investigated. From the results obtained, determine the relations between discharge rate, capacitance and resistance. B. Theories and Hypothesis Theories about Decay of charge Consider a capacitor with capacitance C charged up by a potential difference V, connected across a resistor with constant resistance R. (Figure 1) At any time t, let VR and VC denote the potential difference across R and C respectively, I denotes the current through R, Q denotes the charge remained in C. By Kirchhoff's Laws, Hence, When . Hence Q0 is the initial charge in capacitor. Practically, the charge in a capacitor cannot be measured easily at any time. Therefore current, instead, can be measured. At any time, Or, , where I0 is the initial current through the resistor. Therefore theoretically, it is known that the decay of charge through constant resistance follows an exponential decay pattern. That is, the
Investgating resistivity - Planning and Implementing
This investigation aims to test the relationships within the formula R= ?l/A, resistance in ohms equals resistivity in ohm metres multiplied by length divided into cross-sectional area, and to find a value for the resistivity of constanton (how strongly constanton opposes the flow of an electrical current), ?. I aim to find two values for ?, one to be obtained through an experiment, and the other to be obtained using data books. By obtaining and comparing these two values, I hope to find a reliable and realistic value for constanton's resistivity. Plan of Investigation Apparatus List Just over a metre length of constanton wire, between 0.2mm and 0.4mm in diameter, to be attached using sellotape to a metre rule, calibrated in mm. Variable resistor, 0-12? Digital Ammeter, 0-10 A, +/- 0.005 A Digital Voltmeter, 0-20 V, +/- 0.005V Leads Pair of crocodile clips Micrometer Power pack, supplying 0-2 V, direct current The experiment - Plan First, the metre of constanton wire must be straightened to allow it to be measured accurately. The diameter of this wire should then be measured, using the micrometer. (The zero error of the micrometer must be measured first, to ensure that the value for the diameter is as accurate as possible). Measure the diameter in three places, then compare these results. If they are not equal (to within experimental error) measure the wire's
Ray tracing
Physics GCSE coursework Ray tracing The objective of this experiment is to find the length of an object and its focal lengths. I will first try to hypothesize where the length points will be. The given results of my hypothesized diagrams will determine the lengths of the focal points. I will then be able to find out where the object image will be situated by following my ray trace diagrams. I believe that I will be able to find the length of the object image if I can find the two focal length points ( 1/v and 1/u displayed in my ray trace diagrams and the focal graph). To achieve this I have decided that I could not get an accurate hypothesis if I did not know this information, so I will carry out a small practical experiment. We found that if the lens is thin, the focal length is longer, and if it is thicker, the focal length is smaller. The focal length for our lens is 10cm. I have created some ray tracing diagrams to show my predicted lengths using the focal length that I found. I have found the longest distance that I can get a clear image is 100cm, the shortest being 15cm. I then carried out an experiment to prove my hypothesis. I used light boxes to create a light source, but this is not extremely accurate as the light rays diverge and are not parallel. I used a screen and a lens to try to find an image. My results for my experiment were as follows. I had three
viscosity of golden syrup
An Investigation to Measure the Viscosity of Golden Syrup. Aim: - the aim of my investigation is to measure the viscosity of golden syrup and see if this value depends upon the temperature of the syrup. Apparatus not included in diagram: - micrometer, 5 ball bearings as provided by the school, stop clock, magnet, marker pen, metre rule, weighing scales, thermometer, water bath. (The measuring cylinder is 50 cm3) Certain aspects have to be taken into account to ensure that the experiment is carried out safely. These are: - o If heating the syrup, be careful not to burn yourself on hot equipment. o Goggles should be worn to prevent syrup from entering the eye. Variables that need to be considered are:- the size of the ball bearing to be dropped, the temperature of the syrup, the amount of syrup used, the length that the distance travelled is measured over, the depth beneath the top that the speed and distance are measured from, the type of syrup used and the density of the syrup. I have decided to change the size of the ball bearing to see how this effects viscosity and a further study will be done changing the temperature of the syrup. The differing size ball bearings will be dropped at a constant temperature. To make this a fair test I will have to keep all other variables the same. To do this I will:- o Keep the amount of syrup used, the type of syrup (golden)
Experiment to find the specific heat capacity of an aluminium block.
Experiment to find the specific heat capacity of an aluminium block. DATA COLLECTION: Mass(m) (kg) (5dp) Current(I) (A) (2dp) Voltage (V) (2dp) Time(t) (s) (0dp) Initial temp(T1) (ºC) (2sf) Final temp(T2) (ºC) (2sf) +/-( 5*10^ -4) % +/- (1*10^ -1) % +/- (4*10^ -2) % +/- (5*10^-1)s +/- 0.5 ºC +/- (5*10^ -1) ºC 0.99577 3.70 2.07 0 6.0 6.0 0.99577 3.70 2.08 60 6.0 8.0 0.99577 3.68 2.10 20 6.0 20.0 0.99577 3.66 2.11 80 6.0 22.0 0.99577 3.68 2.10 240 6.0 25.0 0.99577 3.64 2.08 300 6.0 27.0 0.99577 3.64 2.08 360 6.0 30.0 0.99577 3.65 2.03 420 6.0 33.0 DATA PROCESSING AND PRESENTATION: As Q=m.c.(T2-T1) Where Q= energy transfer C= specific heat capacity We can rearrange this to give: C= Q/(m(T2-T1)) And as power = energy/time Therefore E= Pt = Q And P = IV therefore Q = IVt Hence C= IVt/(m(T2-T1)) Which is rearranged to the form y=px + c to give: T2= (IVt / (m.C)) + T1. Where p is the gradient, and equals 1/C, therefore x = IVt/m = Q/m, and y = T2 the y intercept is equal to T1 Therefore I have calculated this table: Energy transfer Errors (J) Q/m (j/kg) Errors(J/kg) Final temp(T2) ( ºC) (2sf) (Q) (J) (0dp) (0dp) (0dp) (0dp) +/- (5*10^ -1) ºC 0 +/- 0 0 +/- 0 6.0 2682 +/- 27 2693 +/- 30 8.0 5343 +/- 32 5366 +/- 30 20.0 7978 +/- 36 8012 +/- 40 22.0 0687 +/- 41 0732 +/-
The Physics of Windsurfing
INTRODUCTION You glide across the surface of the water at unbelievable speeds, steer towards a white capped wave, and then lift off like a bird, each muscle resisting against the force of the wind. Then you smash into the trough of the wave, leap up from near disaster, and look quickly for the next wave so you can do it all over again. This is the exciting sport of windsurfing. THE BEGINNING Windsurfing began in the '60s when an aeronautical engineer and a scientist had a discussion. In 1969, the engineer presented an idea entitled "Wind Surfing: A New Concept in Sailing." This new concept involved releasing the mast from its fixed vertical position and allowing it to turn around its base (Now a days the vertical positioning is not fixed) The sailor then can both steer and balance the board through correct movements of the mast and sail. The early Windsurfer boards measured 12 feet (3.5 m) long and weighed 60 pounds (27 kg). WHAT IS A SAILBOARD? A sailboard is composed of a board and a rig. There is variation in modern sailboards; they generally range from 8 to 12 ft (2 to 4 m) and weigh between 7 to 18 kg; some have attained speeds of over 40 knots CONTROL AND MOVEMENT There is lower pressure on the forward part of the sail and a net force perpendicular to the sail. The net force propels the windsurfer, but part of this force is to the side of the sailboard. The
AS OCR B Advancing Physics Coursework - Making Sense of Data
AS Physics Coursework - Making Sense of Data An experiment was carried out in which the velocity of a falling mass was measured using a light gate: The results are shown in the table below: Height Above Light Gate (mm) Velocity #1 (m/s) Velocity #2 (m/s) Velocity #3 (m/s) 20 0.61 0.62 0.51 70 .12 .11 .10 20 .52 .62 .50 70 .76 .72 .79 220 .93 2.03 .99 270 2.26 2.28 2.30 320 2.45 2.50 2.46 370 2.62 2.67 2.63 420 2.84 2.80 2.89 470 2.96 2.97 2.99 520 3.18 3.13 3.20 570 3.30 3.44 3.34 620 3.53 3.53 3.40 670 3.62 3.64 3.67 720 3.84 3.62 3.83 770 3.86 3.84 3.83 820 4.03 3.97 3.99 870 4.18 4.12 4.14 920 4.36 4.41 4.20 Provided with these results I have initially decided to look at any relationship between the actual figures collected, with the plan of calculating and exploring further data later. I am therefore looking at the relationship between the distance the object fell, and its velocity as it passed through the light gate. An average of the velocities measured in each experiment has been calculated and the height at which the weight was dropped has been multiplied by 1000 to convert it to metres. I have created a graph of these values. Distance fallen /m Average Velocity/ ms-1 0.02 0.58 0.07 .11 0.12 .55 0.17 .76 0.22 .98 0.27 2.28 0.32 2.47 0.37 2.64 0.42 2.84 0.47
Black Holes Research and Report
Contents Page number 3 What is a Black Hole? Black Hole anatomy 4 Types of Black Hole 5 Event horizon radius 6 Mass of a black hole 7 Hawking radiation 8 What happens when Black Holes Collide? Gravitational lensing 10 Einstein rings Evaluation 11 References Black Holes By doing this assignment I aim to gain a better understanding of the physics behind Black Holes What is a Black Hole? To understand a black hole, you must first have an understanding of gravity in space. Imagine yourself on a trampoline; you make an indentation in the trampoline fabric. If someone was to roll a ball past you on the trampoline, it would begin to spiral towards you, down into the indent you have made. This is very similar to the way gravity works in space and time. The 'fabric of spacetime' is an imaginary mesh running through space (see right) which can be deformed and warped by the gravity of stars and planets. This is the principle upon which black holes work. A black hole essentially is an incredibly compact body which has warped space-time enough to make any escape from the force of gravity impossible. They are thought to be at the centre of galaxies, including our own Milky Way. As the name implies, a blackhole cannot emit or reflect any light; making them practically invisible. If enough mass is concentrated into a small enough region, the curvature of
The Compound Pendulum
The Compound Pendulum Task: * To confirm that a metre rule behaves as a compound pendulum when oscillating; * To determine the acceleration due to gravity using a compound pendulum. Planning: Sources used in research of the above tasks are: . A Text-Book of Practical Physics - William Watson; page 129 2. Laboratory Physics - JH Avery & AWK Ingram; page 69 3. Intermediate Physics - CJ Smith; page 50 4. The Text-Book of General Physics - GR Noakes; page 394 5. Intermediate Mechanics - D Humphrey; page 60 6. Introduction to Physics for Scientists and Engineers (Second Edition) - Frederick J. Bueche; page 222 7. http://www.physics.mun.ca/~cdeacon/labs/simonfraser.pdf 8. http://hyperphysics.phy-astr.gsu.edu/hbase/pend.html 9. http://en.wikipedia.org/wiki/Acceleration_due_to_gravity 0. http://geophysics.ou.edu/solid_earth/notes/potential/igf.htm 1. http://www.gorissen.info/Pierre/maps/googleMapLocationv4.php 2. http://en.wikipedia.org/wiki/Reaction_time Where direct quotation is made from a source, the source number is shown in superscript after the preceding italicised quote, e.g. 'quote' 4 . The compound pendulum is defined as: 'a rigid body of any shape and internal structure which is free to turn about a fixed horizontal axis, the only external forces being those due to gravity and the reaction of the axis on the body' 3. In this investigation a wooden
Albert Einstein - The father of modern physics
The Father of modern physics I think it has to be said that Einstein is arguably the most influential scientist of all time, without his work the world of quantum physics, and physics in general, would be a much darker and less understood place. His work has provoked much of the scientific knowledge we have today and has made physics as a whole a more accessible subject for everyone. His wide influence has made him a household name among many families. Einstein is most in famous for the works he produced in the Annus Mirabili – extraordinary year – in this year he produced four papers, these papers were substantial foundations to modern physics. All of these papers were written in German, their translated titles are as follows: “On a Heuristic Viewpoint Concerning the Production and Transformation of Light”, this paper proposed the idea of energy quanta, and put forward an explanation to the Photoelectric Effect. Einstein states that “the energy of a light ray spreading out from a point source is not continuously distributed over an increasing space but consists of a finite number of energy quanta” (Einstein 1905) [1]) this went against the accepted Maxwellian theories of light and radiation, due to this many scientists did not accept this theory, one of these scientists included Niels Bohr, who stated in his Nobel address in 1922 (17 years after Einstein first
