Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userMeasurement of the electron charge $q_e$ using Schottky noise. Problem of the 6-th Experimental Physics Olympiad. Sofia 8 December 2018
59
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
Several consecutive experiments are described with a printed circuit board PCB set-up, especially designed for these experiments. Doing the consecutive experimental tasks opens up possibility to determine the value of electron charge $q_e.$ The fluctuations of the voltage $U(t)$ should be measured for different illuminations of a photodiode. The voltage is amplified 1 million times $Y=10^6$. The amplified voltage $YU(t)$ is applied to the device, which gives the result of the value of the time averaged square of the voltage $U_mathrm{S}=left<(Y U(t))^2right>/U_0$. This voltage $U_mathrm{S}$ is measured with a multimeter. The series of measurements gives the possibility to determine the $q_e$ using the well known Schottky formula for the spectral density of the current noise $(I^2)_f=2q_eleft<Iright>.$ For the junior high school students, the basic problem is to analyze the analog squaring. Students work is separated and graded in four categories S, M, L, XL divided by age of students. For the last XL categories, the tasks contain problems oriented to physics university education program and include theoretical research of the PCB set-up as an engineering device. This is the problem of EPO6, December 2018 ``Day of the Charge considered. EPO6 is organized by Sofia branch of Union of physicists in Bulgaria in cooperation with Faculty of physics of Sofia University and Society of Physicists of Republic of Macedonia.
rate research
Read More
Several consecutive experiments with specifically built set-up are described. Performing of the consecutive experimental tasks enables possibility to determine Boltzmanns constant $k_mathrm{_B}$. The fluctuations of the voltage $U(t)$ of series of capacitors connected in parallel with a constant resistance are measured. The voltage is amplified 1~million times $Y=10^6$. The amplified voltage $YU(t)$ is applied to a device, which give the voltage mean quared in time $U_2=left<(Y U(t))^2right>/U_0$. This voltage $U_2$ is measured with a multimeter. A series of measurements gives the possibility to determine the Boltzmanns constant from the equipartition theorem $Cleft<U^2 right>=k_mathrm{_B}T$. In order to determine the set-up constant $U_0$ a series of problems connected with Ohms law are given that are addressed to the senior students. For the junior high school students, the basic problem is to analyse the analog mean squaring. The students works are graded in four age groups S, M, L, XL. The last age group contains problems that are for university students (XL category) and include theoretical research of the set-up as an engineering device. This problem is given at the Fifth Experimental Physics Olympiad Day of the Electron, on December 2017 in Sofia, organized by the Sofia Branch of the Union of Physicists in Bulgaria with the cooperation of the Physics Faculty of Sofia University and the Society of Physicists of the Republic of Macedonia, Strumica.
This is the problem of the 8$^mathrm{th}$ International Experimental Physics Olympiad (EPO). The task of the EPO8 is to determine Plank constant $hbar=h/2pi$ using the given set-up with LED. If you have an idea how to do it, do it and send us the result; skip the reading of the detailed step by step instructions with increasing difficulties. We expect the participants to follow the suggested items -- they are instructive for physics education in general.Only the reading of historical remarks given in the first section can be omitted during the Olympiad without loss of generality. Participants should try solving as much tasks as they can without paying attention to the age categories: give your best.
A simple experiment for the electron charge $q_e$ measurement is described. The experimental set-up contains standard electronic equipment only and can be built in every high-school lab all around the world with pocket money budget for several days. It is concluded that it is time such a practice to be included in the regular high-school education. The achieved 13% accuracy is comparable to the best student university labs. The measurement is based on Schottky noise generated by a photodiode. Using the criterion dollar per accuracy for the electron charge $q_e$ measurement, this definitely is the worlds best educational experiment. An industrial replica can be easily sold across the globe.
The classic brachistrochrone problem is standard material in intermediate mechanics. Many variations exist including some accessible to introductory students. While a quantitative solution isnt feasible in introductory classes, qualitative discussions can be very beneficial since kinematics, Newtons Laws, energy conservation and motion along curved trajectories all play a role. In this work, we describe an activity focusing on a qualitative understanding of the brachistochrone and examine the performance of freshmen, juniors and graduate students. The activity can be downloaded at https://w3.physics.arizona.edu/undergrad/teaching-resources .
On 31 December 2018 at 10:36:34 UTC shallow earthquake of ML=4.3 took place 25 Km east of Cairo and in the vicinity of the under-construction new Capital city of Egypt (Fig.1). The event was interesting as it was felt with intensity IV up to 50 Km epicentral distance with relatively small magnitude Mw=3.8. the focal mechanism of the event showed Normal faulting with a slight component of strike-slip movement which is in good agreement with the tectonic regime of the area and estimated source parameters are found to be in agreement with intraplate earthquakes. These results could support that the event is triggered by the Pre-Tertiary E-W faults as an on land continuation of the Gulf of Suez extensional process.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
