The document contains multiple choice questions and answers related to topics in physics such as photoelectric effect, electromagnetic radiation, semiconductors, quantum mechanics, atomic structure, nuclear physics, and more. Each question is followed by 4 answer options with one answer marked as correct.
This document discusses matter waves and the photoelectric effect. It explains that Einstein realized the photoelectric effect could be understood if light energy is concentrated in packets called photons rather than spread out over wavefronts. Each photon has an energy equal to Planck's constant times its frequency. This explains key observations like there being no delay between light arriving and electrons emitting, intensity changing the number of electrons but not their energy, and higher frequency light producing faster electrons. De Broglie then suggested this applies generally, so all particles exhibit wave-like properties with a wavelength equal to Planck's constant over momentum.
Chapter3 introduction to the quantum theory of solidsK. M.
The document provides an introduction to the quantum theory of solids, including:
1. How allowed and forbidden energy bands form in solids due to the interaction of atomic electron wave functions when atoms are brought close together in a crystal lattice.
2. Electrical conduction in solids is explained using the concept of electron effective mass and holes, within the framework of the energy band model.
3. The Kronig-Penney model is used to quantitatively relate the energy, wave number, and periodic potential within a solid, resulting in allowed and forbidden energy bands.
09 UNIT-9(Electronics and down of Modern Physics) (1).pptxFatimaAfzal56
The document summarizes key concepts from a lecture on electronics and modern physics:
- Rectification converts alternating current to direct current using diodes in half-wave or full-wave configurations. Full-wave rectification uses two diodes or a bridge rectifier circuit to rectify both halves of the input cycle.
- Blackbody radiation is electromagnetic radiation that follows Planck's law and depends on the temperature of the blackbody. The Stefan-Boltzmann law states that a blackbody's total emissive power is directly proportional to the fourth power of its thermodynamic temperature.
- Photoelectric effect experiments provided evidence that light behaves as quantized packets of energy called photons, as described by Einstein's photo
The document discusses the dual nature of matter and radiation. It provides answers to multiple choice and numerical questions related to photoelectric effect, de Broglie wavelength, and magnetic effect of current. Regarding photoelectric effect, it explains that electron emission from a zinc plate in ultraviolet light is due to the photoelectric effect. It also discusses how kinetic energy of photoelectrons varies with frequency of incident radiation. Regarding magnetic effect of current, it describes how to determine direction and magnitude of magnetic field around current carrying wires using the right hand grip rule. It also solves problems related to forces experienced by charged particles in magnetic fields.
The document discusses the photoelectric effect and its characteristics. It can be summarized as follows:
1) The photoelectric effect occurs only when the frequency of incident radiation is greater than or equal to the threshold frequency, which is different for different metals.
2) The maximum kinetic energy of emitted photoelectrons depends on the frequency of incident radiation and is independent of intensity.
3) The rate of photoelectric emission, and thus the photoelectric current, is directly proportional to the intensity of incident radiation for a frequency greater than the threshold.
1) The document discusses the photoelectric effect and early explanations provided by Planck's quantum theory and Einstein. It describes experiments showing that electrons are emitted from metals when light above a threshold frequency strikes them.
2) Einstein used Planck's idea that energy is emitted and absorbed in discrete quanta to explain the photoelectric effect. He proposed that light consists of discrete packets of energy called photons, and that photons impart their entire energy to electrons.
3) The document also discusses de Broglie's hypothesis that all matter exhibits wave-particle duality, and derives an expression for the de Broglie wavelength of matter particles.
This document outlines topics related to semiconductor physics and optoelectronics physics, including:
1. Free electron theory of metals, Bloch's theorem, energy band diagrams, direct and indirect bandgaps, density of states, and the types of electronic materials including metals, semiconductors and insulators.
2. Lasers, which use stimulated emission of radiation to produce an intense, coherent beam of light. Key concepts covered include spontaneous emission, stimulated absorption, population inversion, and semiconductor lasers.
3. Photodetectors and noise sources, with reference made to the Fermi Golden Rule. The document provides an overview of key concepts that will be covered in more depth within these physics courses.
This document discusses matter waves and the photoelectric effect. It explains that Einstein realized the photoelectric effect could be understood if light energy is concentrated in packets called photons rather than spread out over wavefronts. Each photon has an energy equal to Planck's constant times its frequency. This explains key observations like there being no delay between light arriving and electrons emitting, intensity changing the number of electrons but not their energy, and higher frequency light producing faster electrons. De Broglie then suggested this applies generally, so all particles exhibit wave-like properties with a wavelength equal to Planck's constant over momentum.
Chapter3 introduction to the quantum theory of solidsK. M.
The document provides an introduction to the quantum theory of solids, including:
1. How allowed and forbidden energy bands form in solids due to the interaction of atomic electron wave functions when atoms are brought close together in a crystal lattice.
2. Electrical conduction in solids is explained using the concept of electron effective mass and holes, within the framework of the energy band model.
3. The Kronig-Penney model is used to quantitatively relate the energy, wave number, and periodic potential within a solid, resulting in allowed and forbidden energy bands.
09 UNIT-9(Electronics and down of Modern Physics) (1).pptxFatimaAfzal56
The document summarizes key concepts from a lecture on electronics and modern physics:
- Rectification converts alternating current to direct current using diodes in half-wave or full-wave configurations. Full-wave rectification uses two diodes or a bridge rectifier circuit to rectify both halves of the input cycle.
- Blackbody radiation is electromagnetic radiation that follows Planck's law and depends on the temperature of the blackbody. The Stefan-Boltzmann law states that a blackbody's total emissive power is directly proportional to the fourth power of its thermodynamic temperature.
- Photoelectric effect experiments provided evidence that light behaves as quantized packets of energy called photons, as described by Einstein's photo
The document discusses the dual nature of matter and radiation. It provides answers to multiple choice and numerical questions related to photoelectric effect, de Broglie wavelength, and magnetic effect of current. Regarding photoelectric effect, it explains that electron emission from a zinc plate in ultraviolet light is due to the photoelectric effect. It also discusses how kinetic energy of photoelectrons varies with frequency of incident radiation. Regarding magnetic effect of current, it describes how to determine direction and magnitude of magnetic field around current carrying wires using the right hand grip rule. It also solves problems related to forces experienced by charged particles in magnetic fields.
The document discusses the photoelectric effect and its characteristics. It can be summarized as follows:
1) The photoelectric effect occurs only when the frequency of incident radiation is greater than or equal to the threshold frequency, which is different for different metals.
2) The maximum kinetic energy of emitted photoelectrons depends on the frequency of incident radiation and is independent of intensity.
3) The rate of photoelectric emission, and thus the photoelectric current, is directly proportional to the intensity of incident radiation for a frequency greater than the threshold.
1) The document discusses the photoelectric effect and early explanations provided by Planck's quantum theory and Einstein. It describes experiments showing that electrons are emitted from metals when light above a threshold frequency strikes them.
2) Einstein used Planck's idea that energy is emitted and absorbed in discrete quanta to explain the photoelectric effect. He proposed that light consists of discrete packets of energy called photons, and that photons impart their entire energy to electrons.
3) The document also discusses de Broglie's hypothesis that all matter exhibits wave-particle duality, and derives an expression for the de Broglie wavelength of matter particles.
This document outlines topics related to semiconductor physics and optoelectronics physics, including:
1. Free electron theory of metals, Bloch's theorem, energy band diagrams, direct and indirect bandgaps, density of states, and the types of electronic materials including metals, semiconductors and insulators.
2. Lasers, which use stimulated emission of radiation to produce an intense, coherent beam of light. Key concepts covered include spontaneous emission, stimulated absorption, population inversion, and semiconductor lasers.
3. Photodetectors and noise sources, with reference made to the Fermi Golden Rule. The document provides an overview of key concepts that will be covered in more depth within these physics courses.
This document discusses semiconductor nanostructures, specifically summarizing key concepts about quantum wells, wires, and dots. It begins by providing a brief history of semiconductors and introducing how nanostructures exhibit quantum effects. It then discusses the basic physics behind semiconductor nanostructures, including De Broglie wavelength, quantum wells, and how the density of states varies between 3D, 2D, 1D and 0D structures. Finally, it covers fabrication methods like molecular beam epitaxy that are used to grow nanostructures through layer-by-layer deposition in an ultra-high vacuum.
The document defines and explains various quantities and units used in radiation dosimetry, including:
- Particle fluence, energy fluence, and related rates, which describe radiation beams.
- Kerma and cema, which quantify energy transferred from indirect and direct radiation.
- Absorbed dose, which measures energy imparted to matter.
- Stopping power, which expresses the rate of energy loss by charged particles through interactions. Both unrestricted and restricted stopping powers are discussed.
[1] Photoelectric effect provides evidence that light behaves as particles called photons, with each photon having energy hν. This explains the threshold frequency and instantaneous emission.
[2] Compton scattering demonstrates that photons transfer discrete packets of energy and momentum to electrons during collisions, with the photon's wavelength increasing in accordance with conservation laws. This provided direct evidence that photons are real particles.
[3] Pair production demonstrates that a photon's energy can be converted into an electron-positron pair, as predicted by Einstein's equation E=mc2. A minimum photon energy of 1.02 MeV is required to produce the pairs.
This document provides information on the dual nature of matter and radiation, including photoelectric effect questions and answers. It discusses key concepts such as:
- The photoelectric effect and how an uncharged zinc plate becomes positively charged when irradiated by ultraviolet radiation.
- Graphs showing the relationship between photoelectric current and anode potential when frequency is kept constant.
- Questions regarding the wave-particle duality of matter and radiation, including the de Broglie wavelength equation.
- Multi-part questions analyzing graphs and equations related to the photoelectric effect and Einstein's photoelectric equation.
This document discusses the dual nature of matter and radiation, including photoelectric effect and de Broglie wavelength. It provides 5 one-mark questions and answers on topics like photoelectric effect and characteristics of incident radiation. It also gives 5 two-mark questions and answers exploring topics such as kinetic energy relationship between an electron and alpha particle with the same de-Broglie wavelength. Finally, it provides 5 three-mark questions and answers examining Einstein's photoelectric equation and variations in photoelectric experiments.
Lecture06h Frequency Dependent Transport5.pptHanzlaAhmad2
1) The document discusses electromagnetic waves propagating through metal. Waves with frequencies above the plasma frequency of the metal (wp) can propagate through, while waves with frequencies below wp are reflected.
2) It also describes the skin effect - waves below wp are damped as they penetrate the metal, with their amplitude decreasing exponentially with a penetration depth d.
3) The document contrasts longitudinal plasma oscillations of the electron gas at the plasma frequency wp with transverse electromagnetic waves in metals.
This document discusses radiation interactions with matter. It describes how different types of ionizing radiation interact with and deposit energy in matter. Photons can interact via photoelectric effect, Compton scattering, and pair production. Charged particles like electrons cause ionization and excitation as they pass through matter. Neutrons interact with nuclei via collisions or nuclear disintegration. The effectiveness of different types of interactions depends on the energy of the radiation and the atomic properties of the absorbing material. Depth dose profiles are compared for different particle beams like photons, electrons, protons, and neutrons.
This document discusses key concepts about electric charge including:
- Charges of the same sign repel and opposite charges attract based on Coulomb's law.
- Conductors allow free movement of charge carriers like electrons, while insulators do not.
- Charge is quantized and can only exist in integer multiples of the elementary charge carried by protons and electrons.
- Charge is conserved in interactions and transformations at both the macro and microscopic level.
Determine Planck constant using the photoelectric effect.UCP
This document describes an experiment to determine Planck's constant using the photoelectric effect. A phototube apparatus with different color filters is used to measure the maximum kinetic energy of electrons emitted from a metal surface when illuminated by light of varying frequencies. The results show a linear relationship between stopping potential and light frequency, from which Planck's constant and the work function of the metal can be extracted. The experiment verifies Einstein's explanation of the photoelectric effect and provides a method to calculate Planck's constant.
This document contains a 50 question physics exam with multiple choice answers. The questions cover topics in physics including X-rays, electron motion in electric and magnetic fields, wavelength of electrons, projectile motion, optics, atomic structure, electricity, magnetism, and more. For each question there are typically 4 possible answers labeled a, b, c, or d.
Physics Sample Paper with General Instruction for Class - 12Learning Three Sixty
Learning 360 brings “Physics sample paper” for CLASS – 12. This document also carries 31 questions with solution of each given question for better understanding of the students. Download for free now; http://www.learning360.net/study_hub/1090-2/
This document contains a summary of several physics concepts related to wave-particle duality and quantum physics. It includes 3 sample problems worked out in detail that demonstrate: 1) using the Compton scattering equation to estimate the Compton wavelength from experimental data, 2) relating the number of photons emitted by a laser to its power and photon energy, and 3) calculating the energy of the most energetic electron in uranium using the particle in a box model. The worked problems provide insight into applying relevant equations and show the conceptual and mathematical steps.
This document contains a 52 slide summary of Chapter 2 from the IAEA publication "Diagnostic Radiology Physics: A Handbook for Teachers and Students". The chapter discusses the physics of interactions between photons, electrons, and matter in diagnostic radiology. It covers the photoelectric effect, coherent (Rayleigh) scattering, incoherent scattering, and pair and triplet production interactions between photons and atoms. It also discusses electron interactions with matter and how photon and electron interactions are expressed using cross-sections and attenuation coefficients.
This document provides a sample test paper for Class XII Physics with 35 questions divided into 5 sections (A-E). Section A contains 18 multiple choice questions worth 1 mark each. Section B contains 7 questions worth 2 marks each. Section C contains 5 questions worth 3 marks each. Section D contains 3 questions worth 5 marks each. Section E contains 2 case study questions worth 4 marks each. The test covers topics such as photoelectric effect, electromagnetic waves, electric and magnetic fields, interference and diffraction. Students are instructed that calculators are not allowed and all questions are compulsory.
1. The document discusses the electron theory of solids, which aims to explain the structures and properties of solids through their electronic structure.
2. It describes three main stages in the development of the electron theory of solids: the classical free electron theory developed in 1900, the quantum free electron theory developed in 1928, and Bloch's zone theory also developed in 1928, known as the band theory of solids.
3. The quantum free electron theory overcomes many drawbacks of the classical theory by applying quantum mechanics and using Fermi-Dirac statistics instead of Maxwell-Boltzmann statistics.
1) Maxwell's equations are used to derive the wave equation for electromagnetic waves traveling in the x direction.
2) The electric and magnetic fields are shown to oscillate perpendicular to each other and the direction of propagation at the speed of light c.
3) The intensity of the electromagnetic wave, which determines its brightness or loudness, is directly proportional to the square of the amplitudes of the electric and magnetic fields.
This document summarizes Louis de Broglie's hypothesis of wave-particle duality and its applications. It discusses de Broglie's proposal that particles have wave-like properties with a wavelength given by Planck's constant divided by momentum. The photoelectric effect and Compton effect provide evidence of wave and particle behavior of light and electrons. Wave-particle duality is exploited in technologies like electron microscopy and neutron diffraction to examine structures smaller than visible light wavelengths. While useful, wave-particle duality does not fully explain quantum phenomena like the Heisenberg uncertainty principle.
This document discusses semiconductor nanostructures, specifically summarizing key concepts about quantum wells, wires, and dots. It begins by providing a brief history of semiconductors and introducing how nanostructures exhibit quantum effects. It then discusses the basic physics behind semiconductor nanostructures, including De Broglie wavelength, quantum wells, and how the density of states varies between 3D, 2D, 1D and 0D structures. Finally, it covers fabrication methods like molecular beam epitaxy that are used to grow nanostructures through layer-by-layer deposition in an ultra-high vacuum.
The document defines and explains various quantities and units used in radiation dosimetry, including:
- Particle fluence, energy fluence, and related rates, which describe radiation beams.
- Kerma and cema, which quantify energy transferred from indirect and direct radiation.
- Absorbed dose, which measures energy imparted to matter.
- Stopping power, which expresses the rate of energy loss by charged particles through interactions. Both unrestricted and restricted stopping powers are discussed.
[1] Photoelectric effect provides evidence that light behaves as particles called photons, with each photon having energy hν. This explains the threshold frequency and instantaneous emission.
[2] Compton scattering demonstrates that photons transfer discrete packets of energy and momentum to electrons during collisions, with the photon's wavelength increasing in accordance with conservation laws. This provided direct evidence that photons are real particles.
[3] Pair production demonstrates that a photon's energy can be converted into an electron-positron pair, as predicted by Einstein's equation E=mc2. A minimum photon energy of 1.02 MeV is required to produce the pairs.
This document provides information on the dual nature of matter and radiation, including photoelectric effect questions and answers. It discusses key concepts such as:
- The photoelectric effect and how an uncharged zinc plate becomes positively charged when irradiated by ultraviolet radiation.
- Graphs showing the relationship between photoelectric current and anode potential when frequency is kept constant.
- Questions regarding the wave-particle duality of matter and radiation, including the de Broglie wavelength equation.
- Multi-part questions analyzing graphs and equations related to the photoelectric effect and Einstein's photoelectric equation.
This document discusses the dual nature of matter and radiation, including photoelectric effect and de Broglie wavelength. It provides 5 one-mark questions and answers on topics like photoelectric effect and characteristics of incident radiation. It also gives 5 two-mark questions and answers exploring topics such as kinetic energy relationship between an electron and alpha particle with the same de-Broglie wavelength. Finally, it provides 5 three-mark questions and answers examining Einstein's photoelectric equation and variations in photoelectric experiments.
Lecture06h Frequency Dependent Transport5.pptHanzlaAhmad2
1) The document discusses electromagnetic waves propagating through metal. Waves with frequencies above the plasma frequency of the metal (wp) can propagate through, while waves with frequencies below wp are reflected.
2) It also describes the skin effect - waves below wp are damped as they penetrate the metal, with their amplitude decreasing exponentially with a penetration depth d.
3) The document contrasts longitudinal plasma oscillations of the electron gas at the plasma frequency wp with transverse electromagnetic waves in metals.
This document discusses radiation interactions with matter. It describes how different types of ionizing radiation interact with and deposit energy in matter. Photons can interact via photoelectric effect, Compton scattering, and pair production. Charged particles like electrons cause ionization and excitation as they pass through matter. Neutrons interact with nuclei via collisions or nuclear disintegration. The effectiveness of different types of interactions depends on the energy of the radiation and the atomic properties of the absorbing material. Depth dose profiles are compared for different particle beams like photons, electrons, protons, and neutrons.
This document discusses key concepts about electric charge including:
- Charges of the same sign repel and opposite charges attract based on Coulomb's law.
- Conductors allow free movement of charge carriers like electrons, while insulators do not.
- Charge is quantized and can only exist in integer multiples of the elementary charge carried by protons and electrons.
- Charge is conserved in interactions and transformations at both the macro and microscopic level.
Determine Planck constant using the photoelectric effect.UCP
This document describes an experiment to determine Planck's constant using the photoelectric effect. A phototube apparatus with different color filters is used to measure the maximum kinetic energy of electrons emitted from a metal surface when illuminated by light of varying frequencies. The results show a linear relationship between stopping potential and light frequency, from which Planck's constant and the work function of the metal can be extracted. The experiment verifies Einstein's explanation of the photoelectric effect and provides a method to calculate Planck's constant.
This document contains a 50 question physics exam with multiple choice answers. The questions cover topics in physics including X-rays, electron motion in electric and magnetic fields, wavelength of electrons, projectile motion, optics, atomic structure, electricity, magnetism, and more. For each question there are typically 4 possible answers labeled a, b, c, or d.
Physics Sample Paper with General Instruction for Class - 12Learning Three Sixty
Learning 360 brings “Physics sample paper” for CLASS – 12. This document also carries 31 questions with solution of each given question for better understanding of the students. Download for free now; http://www.learning360.net/study_hub/1090-2/
This document contains a summary of several physics concepts related to wave-particle duality and quantum physics. It includes 3 sample problems worked out in detail that demonstrate: 1) using the Compton scattering equation to estimate the Compton wavelength from experimental data, 2) relating the number of photons emitted by a laser to its power and photon energy, and 3) calculating the energy of the most energetic electron in uranium using the particle in a box model. The worked problems provide insight into applying relevant equations and show the conceptual and mathematical steps.
This document contains a 52 slide summary of Chapter 2 from the IAEA publication "Diagnostic Radiology Physics: A Handbook for Teachers and Students". The chapter discusses the physics of interactions between photons, electrons, and matter in diagnostic radiology. It covers the photoelectric effect, coherent (Rayleigh) scattering, incoherent scattering, and pair and triplet production interactions between photons and atoms. It also discusses electron interactions with matter and how photon and electron interactions are expressed using cross-sections and attenuation coefficients.
This document provides a sample test paper for Class XII Physics with 35 questions divided into 5 sections (A-E). Section A contains 18 multiple choice questions worth 1 mark each. Section B contains 7 questions worth 2 marks each. Section C contains 5 questions worth 3 marks each. Section D contains 3 questions worth 5 marks each. Section E contains 2 case study questions worth 4 marks each. The test covers topics such as photoelectric effect, electromagnetic waves, electric and magnetic fields, interference and diffraction. Students are instructed that calculators are not allowed and all questions are compulsory.
1. The document discusses the electron theory of solids, which aims to explain the structures and properties of solids through their electronic structure.
2. It describes three main stages in the development of the electron theory of solids: the classical free electron theory developed in 1900, the quantum free electron theory developed in 1928, and Bloch's zone theory also developed in 1928, known as the band theory of solids.
3. The quantum free electron theory overcomes many drawbacks of the classical theory by applying quantum mechanics and using Fermi-Dirac statistics instead of Maxwell-Boltzmann statistics.
1) Maxwell's equations are used to derive the wave equation for electromagnetic waves traveling in the x direction.
2) The electric and magnetic fields are shown to oscillate perpendicular to each other and the direction of propagation at the speed of light c.
3) The intensity of the electromagnetic wave, which determines its brightness or loudness, is directly proportional to the square of the amplitudes of the electric and magnetic fields.
This document summarizes Louis de Broglie's hypothesis of wave-particle duality and its applications. It discusses de Broglie's proposal that particles have wave-like properties with a wavelength given by Planck's constant divided by momentum. The photoelectric effect and Compton effect provide evidence of wave and particle behavior of light and electrons. Wave-particle duality is exploited in technologies like electron microscopy and neutron diffraction to examine structures smaller than visible light wavelengths. While useful, wave-particle duality does not fully explain quantum phenomena like the Heisenberg uncertainty principle.
The use of Nauplii and metanauplii artemia in aquaculture (brine shrimp).pptxMAGOTI ERNEST
Although Artemia has been known to man for centuries, its use as a food for the culture of larval organisms apparently began only in the 1930s, when several investigators found that it made an excellent food for newly hatched fish larvae (Litvinenko et al., 2023). As aquaculture developed in the 1960s and ‘70s, the use of Artemia also became more widespread, due both to its convenience and to its nutritional value for larval organisms (Arenas-Pardo et al., 2024). The fact that Artemia dormant cysts can be stored for long periods in cans, and then used as an off-the-shelf food requiring only 24 h of incubation makes them the most convenient, least labor-intensive, live food available for aquaculture (Sorgeloos & Roubach, 2021). The nutritional value of Artemia, especially for marine organisms, is not constant, but varies both geographically and temporally. During the last decade, however, both the causes of Artemia nutritional variability and methods to improve poorquality Artemia have been identified (Loufi et al., 2024).
Brine shrimp (Artemia spp.) are used in marine aquaculture worldwide. Annually, more than 2,000 metric tons of dry cysts are used for cultivation of fish, crustacean, and shellfish larva. Brine shrimp are important to aquaculture because newly hatched brine shrimp nauplii (larvae) provide a food source for many fish fry (Mozanzadeh et al., 2021). Culture and harvesting of brine shrimp eggs represents another aspect of the aquaculture industry. Nauplii and metanauplii of Artemia, commonly known as brine shrimp, play a crucial role in aquaculture due to their nutritional value and suitability as live feed for many aquatic species, particularly in larval stages (Sorgeloos & Roubach, 2021).
Unlocking the mysteries of reproduction: Exploring fecundity and gonadosomati...AbdullaAlAsif1
The pygmy halfbeak Dermogenys colletei, is known for its viviparous nature, this presents an intriguing case of relatively low fecundity, raising questions about potential compensatory reproductive strategies employed by this species. Our study delves into the examination of fecundity and the Gonadosomatic Index (GSI) in the Pygmy Halfbeak, D. colletei (Meisner, 2001), an intriguing viviparous fish indigenous to Sarawak, Borneo. We hypothesize that the Pygmy halfbeak, D. colletei, may exhibit unique reproductive adaptations to offset its low fecundity, thus enhancing its survival and fitness. To address this, we conducted a comprehensive study utilizing 28 mature female specimens of D. colletei, carefully measuring fecundity and GSI to shed light on the reproductive adaptations of this species. Our findings reveal that D. colletei indeed exhibits low fecundity, with a mean of 16.76 ± 2.01, and a mean GSI of 12.83 ± 1.27, providing crucial insights into the reproductive mechanisms at play in this species. These results underscore the existence of unique reproductive strategies in D. colletei, enabling its adaptation and persistence in Borneo's diverse aquatic ecosystems, and call for further ecological research to elucidate these mechanisms. This study lends to a better understanding of viviparous fish in Borneo and contributes to the broader field of aquatic ecology, enhancing our knowledge of species adaptations to unique ecological challenges.
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...Sérgio Sacani
Context. With a mass exceeding several 104 M⊙ and a rich and dense population of massive stars, supermassive young star clusters
represent the most massive star-forming environment that is dominated by the feedback from massive stars and gravitational interactions
among stars.
Aims. In this paper we present the Extended Westerlund 1 and 2 Open Clusters Survey (EWOCS) project, which aims to investigate
the influence of the starburst environment on the formation of stars and planets, and on the evolution of both low and high mass stars.
The primary targets of this project are Westerlund 1 and 2, the closest supermassive star clusters to the Sun.
Methods. The project is based primarily on recent observations conducted with the Chandra and JWST observatories. Specifically,
the Chandra survey of Westerlund 1 consists of 36 new ACIS-I observations, nearly co-pointed, for a total exposure time of 1 Msec.
Additionally, we included 8 archival Chandra/ACIS-S observations. This paper presents the resulting catalog of X-ray sources within
and around Westerlund 1. Sources were detected by combining various existing methods, and photon extraction and source validation
were carried out using the ACIS-Extract software.
Results. The EWOCS X-ray catalog comprises 5963 validated sources out of the 9420 initially provided to ACIS-Extract, reaching a
photon flux threshold of approximately 2 × 10−8 photons cm−2
s
−1
. The X-ray sources exhibit a highly concentrated spatial distribution,
with 1075 sources located within the central 1 arcmin. We have successfully detected X-ray emissions from 126 out of the 166 known
massive stars of the cluster, and we have collected over 71 000 photons from the magnetar CXO J164710.20-455217.
Remote Sensing and Computational, Evolutionary, Supercomputing, and Intellige...University of Maribor
Slides from talk:
Aleš Zamuda: Remote Sensing and Computational, Evolutionary, Supercomputing, and Intelligent Systems.
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Inter-Society Networking Panel GRSS/MTT-S/CIS Panel Session: Promoting Connection and Cooperation
https://www.etran.rs/2024/en/home-english/
Current Ms word generated power point presentation covers major details about the micronuclei test. It's significance and assays to conduct it. It is used to detect the micronuclei formation inside the cells of nearly every multicellular organism. It's formation takes place during chromosomal sepration at metaphase.
The ability to recreate computational results with minimal effort and actionable metrics provides a solid foundation for scientific research and software development. When people can replicate an analysis at the touch of a button using open-source software, open data, and methods to assess and compare proposals, it significantly eases verification of results, engagement with a diverse range of contributors, and progress. However, we have yet to fully achieve this; there are still many sociotechnical frictions.
Inspired by David Donoho's vision, this talk aims to revisit the three crucial pillars of frictionless reproducibility (data sharing, code sharing, and competitive challenges) with the perspective of deep software variability.
Our observation is that multiple layers — hardware, operating systems, third-party libraries, software versions, input data, compile-time options, and parameters — are subject to variability that exacerbates frictions but is also essential for achieving robust, generalizable results and fostering innovation. I will first review the literature, providing evidence of how the complex variability interactions across these layers affect qualitative and quantitative software properties, thereby complicating the reproduction and replication of scientific studies in various fields.
I will then present some software engineering and AI techniques that can support the strategic exploration of variability spaces. These include the use of abstractions and models (e.g., feature models), sampling strategies (e.g., uniform, random), cost-effective measurements (e.g., incremental build of software configurations), and dimensionality reduction methods (e.g., transfer learning, feature selection, software debloating).
I will finally argue that deep variability is both the problem and solution of frictionless reproducibility, calling the software science community to develop new methods and tools to manage variability and foster reproducibility in software systems.
Exposé invité Journées Nationales du GDR GPL 2024
hematic appreciation test is a psychological assessment tool used to measure an individual's appreciation and understanding of specific themes or topics. This test helps to evaluate an individual's ability to connect different ideas and concepts within a given theme, as well as their overall comprehension and interpretation skills. The results of the test can provide valuable insights into an individual's cognitive abilities, creativity, and critical thinking skills
Authoring a personal GPT for your research and practice: How we created the Q...Leonel Morgado
Thematic analysis in qualitative research is a time-consuming and systematic task, typically done using teams. Team members must ground their activities on common understandings of the major concepts underlying the thematic analysis, and define criteria for its development. However, conceptual misunderstandings, equivocations, and lack of adherence to criteria are challenges to the quality and speed of this process. Given the distributed and uncertain nature of this process, we wondered if the tasks in thematic analysis could be supported by readily available artificial intelligence chatbots. Our early efforts point to potential benefits: not just saving time in the coding process but better adherence to criteria and grounding, by increasing triangulation between humans and artificial intelligence. This tutorial will provide a description and demonstration of the process we followed, as two academic researchers, to develop a custom ChatGPT to assist with qualitative coding in the thematic data analysis process of immersive learning accounts in a survey of the academic literature: QUAL-E Immersive Learning Thematic Analysis Helper. In the hands-on time, participants will try out QUAL-E and develop their ideas for their own qualitative coding ChatGPT. Participants that have the paid ChatGPT Plus subscription can create a draft of their assistants. The organizers will provide course materials and slide deck that participants will be able to utilize to continue development of their custom GPT. The paid subscription to ChatGPT Plus is not required to participate in this workshop, just for trying out personal GPTs during it.
Or: Beyond linear.
Abstract: Equivariant neural networks are neural networks that incorporate symmetries. The nonlinear activation functions in these networks result in interesting nonlinear equivariant maps between simple representations, and motivate the key player of this talk: piecewise linear representation theory.
Disclaimer: No one is perfect, so please mind that there might be mistakes and typos.
dtubbenhauer@gmail.com
Corrected slides: dtubbenhauer.com/talks.html
The debris of the ‘last major merger’ is dynamically youngSérgio Sacani
The Milky Way’s (MW) inner stellar halo contains an [Fe/H]-rich component with highly eccentric orbits, often referred to as the
‘last major merger.’ Hypotheses for the origin of this component include Gaia-Sausage/Enceladus (GSE), where the progenitor
collided with the MW proto-disc 8–11 Gyr ago, and the Virgo Radial Merger (VRM), where the progenitor collided with the
MW disc within the last 3 Gyr. These two scenarios make different predictions about observable structure in local phase space,
because the morphology of debris depends on how long it has had to phase mix. The recently identified phase-space folds in Gaia
DR3 have positive caustic velocities, making them fundamentally different than the phase-mixed chevrons found in simulations
at late times. Roughly 20 per cent of the stars in the prograde local stellar halo are associated with the observed caustics. Based
on a simple phase-mixing model, the observed number of caustics are consistent with a merger that occurred 1–2 Gyr ago.
We also compare the observed phase-space distribution to FIRE-2 Latte simulations of GSE-like mergers, using a quantitative
measurement of phase mixing (2D causticality). The observed local phase-space distribution best matches the simulated data
1–2 Gyr after collision, and certainly not later than 3 Gyr. This is further evidence that the progenitor of the ‘last major merger’
did not collide with the MW proto-disc at early times, as is thought for the GSE, but instead collided with the MW disc within
the last few Gyr, consistent with the body of work surrounding the VRM.
The binding of cosmological structures by massless topological defectsSérgio Sacani
Assuming spherical symmetry and weak field, it is shown that if one solves the Poisson equation or the Einstein field
equations sourced by a topological defect, i.e. a singularity of a very specific form, the result is a localized gravitational
field capable of driving flat rotation (i.e. Keplerian circular orbits at a constant speed for all radii) of test masses on a thin
spherical shell without any underlying mass. Moreover, a large-scale structure which exploits this solution by assembling
concentrically a number of such topological defects can establish a flat stellar or galactic rotation curve, and can also deflect
light in the same manner as an equipotential (isothermal) sphere. Thus, the need for dark matter or modified gravity theory is
mitigated, at least in part.
18. A
C
D
B
26 March -
shift 1, 2021
Phase
Intensity
Amplitude
Frequency
The stopping potential in the context of photoelectric effect
depends on the following property of incident electromagnetic
radiation:
19. A
C
D
B
26 March -
shift 1, 2021
Phase
Intensity
Amplitude
Frequency
The stopping potential in the context of photoelectric effect
depends on the following property of incident electromagnetic
radiation:
20. 25 July - shift 1
2022
The energy band gap of semiconducting material to produce violet
(wavelength = 4000 Å) LED is _____ eV. (Round off to the nearest
integer).
21.
22. 25 July - shift 1
2022
The energy band gap of semiconducting material to produce violet
(wavelength = 4000 Å) LED is _3_ eV. (Round off to the nearest
integer).
23. A
C
D
B
27 Aug -
Shift 1, 2021
Increases the number of photons incident and also
increases the K.E. of the ejected electrons
Increases the frequency of photons incident and
increases the K.E. of the ejected electrons
Increases the frequency of photons incident and the
K.E. of the ejected electrons remains unchanged
Increases the number of photons incident and the
K.E. of the ejected electrons remains unchanged
In a photoelectric experiment, increasing the intensity of incident
light:
24. A
C
D
B
27 Aug -
Shift 1, 2021
Increases the number of photons incident and also
increases the K.E. of the ejected electrons
Increases the frequency of photons incident and
increases the K.E. of the ejected electrons
Increases the frequency of photons incident and the
K.E. of the ejected electrons remains unchanged
Increases the number of photons incident and the
K.E. of the ejected electrons remains unchanged
In a photoelectric experiment, increasing the intensity of incident
light:
25. A
C
D
B
25 July - shift 1
2022
1.537 eV
A metal exposed to light of wavelength 800 nm and emits
photoelectrons with a certain kinetic energy. The maximum kinetic
energy of photoelectron doubles when light of wavelength 500 nm is
used. The work function of the metal (Take hc = 1230 eV-nm).
2.46 eV
0.615 eV
1.23 eV
26.
27. A
C
D
B
25 July - shift 1
2022
1.537 eV
A metal exposed to light of wavelength 800 nm and emits
photoelectrons with a certain kinetic energy. The maximum kinetic
energy of photoelectron doubles when light of wavelength 500 nm is
used. The work function of the metal (Take hc = 1230 eV-nm).
2.46 eV
0.615 eV
1.23 eV
28. 20 July -
Shift 2, 2021
A certain metallic surface is illuminated by monochromatic radiation
of wavelength λ. The stopping potential for photoelectric current for
this radiation is 3 V0. If the same surface is illuminated with a
radiation of wavelength 2λ, the stopping potential is V0. The
threshold wavelength of this surface for photoelectric effect is___ λ
29.
30. 20 July -
Shift 2, 2021
A certain metallic surface is illuminated by monochromatic radiation
of wavelength λ. The stopping potential for photoelectric current for
this radiation is 3 V0. If the same surface is illuminated with a
radiation of wavelength 2λ, the stopping potential is V0. The
threshold wavelength of this surface for photoelectric effect is_4_ λ
31. A
C
D
B
24 June - shift 2
2022
1 : 1
2 : 1
4 : 1
1 : 4
The light of two different frequencies whose photons have energies
3.8 eV and 1.4 eV respectively, illuminate a metallic surface whose
work function is 0.6 eV successively. The ratio of maximum speeds
of emitted electrons for the two frequencies respectively will be:
32.
33. A
C
D
B
24 June - shift 2
2022
1 : 1
2 : 1
4 : 1
1 : 4
The light of two different frequencies whose photons have energies
3.8 eV and 1.4 eV respectively, illuminate a metallic surface whose
work function is 0.6 eV successively. The ratio of maximum speeds
of emitted electrons for the two frequencies respectively will be:
34. A
C
D
B
28 July - shift 2
2022
1 : 2
Two streams of photons, possessing energies, five and ten times the
work function of metal are incident on the metal surface
successively. The ratio of the maximum velocities of the
photoelectron emitted, in the two cases respectively, will be
1 : 3
2 : 3
3 : 2
35.
36. A
C
D
B
28 July - shift 2
2022
1 : 2
Two streams of photons, possessing energies, five and ten times the
work function of metal are incident on the metal surface
successively. The ratio of the maximum velocities of the
photoelectron emitted, in the two cases respectively, will be
1 : 3
2 : 3
3 : 2
37. 26 Feb - shift 2
2021
Two stream of photons, possessing energies equal to twice and ten
times the work function of metal are incident on the metal surface
successively. The value of ratio of maximum velocities of the
photoelectrons emitted in the two respective cases is x : y. The value
of x is
38.
39. 26 Feb - shift 2
2021
Two stream of photons, possessing energies equal to twice and ten
times the work function of metal are incident on the metal surface
successively. The value of ratio of maximum velocities of the
photoelectrons emitted in the two respective cases is x : y. The value
of x is_1_
40. A
C
D
B
29 June - shift 2
2022
1.90 eV
The electric field at the point associated with a light wave is given by
E = 200 [sin(6 × 1015] t + sin(9 × 1015) t] Vm-1
Given: h = 4.14 × 10-15 eVs
If this light falls on a metal surface having a work function of 2.50 eV,
the maximum kinetic energy of the photoelectrons will be:
3.27 eV
3.60 eV
3.42 eV
41.
42. A
C
D
B
29 June - shift 2
2022
1.90 eV
The electric field at the point associated with a light wave is given by
E = 200 [sin(6 × 1015] t + sin(9 × 1015) t] Vm-1
Given: h = 4.14 × 10-15 eVs
If this light falls on a metal surface having a work function of 2.50 eV,
the maximum kinetic energy of the photoelectrons will be:
3,27 eV
3.60 eV
3.42 eV
43. A
C
D
B
28 June - shift 2
2022
Let K1 and K2 be the maximum kinetic energies of photoelectrons
emitted when two monochromatic beams of wavelength 𝜆1 and 𝜆2,
respectively are incident on a metallic surface. If 𝜆1 = 3𝜆2 then:
44.
45. A
C
D
B
28 June - shift 2
2022
Let K1 and K2 be the maximum kinetic energies of photoelectrons
emitted when two monochromatic beams of wavelength 𝜆1 and 𝜆2,
respectively are incident on a metallic surface. If 𝜆1 = 3𝜆2 then:
46.
47.
48. A
C
D
B
28 July - shift 1
2022
The equation can be used to find the de-Broglie
wavelength of an electron. In this equation x stands for:
Where
m = mass of electron
P = momentum of electron
K = Kinetic energy of electron
V = Accelerating potential in volts for electron
49.
50. A
C
D
B
28 July - shift 1
2022
The equation can be used to find the de-Broglie
wavelength of an electron. In this equation x stands for:
Where
m = mass of electron
P = momentum of electron
K = Kinetic energy of electron
V = Accelerating potential in volts for electron
51. A
C
D
B
25 July - shift 2
2022
1 : 1
The ratio of wavelengths of proton and deuteron accelerated by
potential Vp and Vd is Then, the ratio of Vp to Vd will be
2 : 1
4 : 1
52.
53. A
C
D
B
25 July - shift 2
2022
1 : 1
The ratio of wavelengths of proton and deuteron accelerated by
potential Vp and Vd is Then, the ratio of Vp to Vd will be
2 : 1
4 : 1
54. A
C
D
B
29 July - shift 2
2022
An α particle and a proton are accelerated from rest through the
same potential difference. The ratio of linear momenta acquired by
above two particles will be:
8 : 1
55.
56. A
C
D
B
29 July - shift 2
2022
An α particle and a proton are accelerated from rest through the
same potential difference. The ratio of linear momenta acquired by
above two particles will be:
8 : 1
57. A
C
D
B
28 June - shift 1
2022
𝜆p ∝ 𝜆e
2
The de-Broglie wavelength for an electron and a photon are 𝜆e and 𝜆p
respectively. For the same kinetic energy of electron and photon
which of the following presents the correct relation between the de-
Broglie wavelengths of two?
𝜆p ∝ 𝜆e
58.
59. A
C
D
B
28 June - shift 1
2022
𝜆p ∝ 𝜆e
2
The de-Broglie wavelength for an electron and a photon are 𝜆e and 𝜆p
respectively. For the same kinetic energy of electron and photon
which of the following presents the correct relation between the de-
Broglie wavelengths of two?
𝜆p ∝ 𝜆e
60. A
C
D
B
26 June - shift 1
2022
An electron with speed v and a photon with speed c have the same
de-Broglie wavelength. If the kinetic energy and momentum of
electron are Ee and pe and that of photon are Eph and pph respectively.
Which of the following is correct?
61.
62. A
C
D
B
26 June - shift 1
2022
An electron with speed v and a photon with speed c have the same
de-Broglie wavelength. If the kinetic energy and momentum of
electron are Ee and pe and that of photon are Eph and pph respectively.
Which of the following is correct?
63. A
C
D
B
25 June - shift 2
2022
𝜆p = 𝜆n > 𝜆e > 𝜆α
A proton, a neutron, an electron and an α-particle have same energy.
If 𝜆p, 𝜆n, 𝜆e and 𝜆α are the de-Broglie’s wavelength of proton, neutron,
electron and α particle respectively, then choose the correct relation
from the following:
𝜆α < 𝜆n < 𝜆p < 𝜆e
𝜆e < 𝜆p = 𝜆n > 𝜆α
𝜆e = 𝜆p = 𝜆n = 𝜆α
64.
65. A
C
D
B
25 June - shift 2
2022
𝜆p = 𝜆n > 𝜆e > 𝜆α
A proton, a neutron, an electron and an α-particle have same energy.
If 𝜆p, 𝜆n, 𝜆e and 𝜆α are the de-Broglie’s wavelength of proton, neutron,
electron and α particle respectively, then choose the correct relation
from the following:
𝜆α < 𝜆n < 𝜆p < 𝜆e
𝜆e < 𝜆p = 𝜆n > 𝜆α
𝜆e = 𝜆p = 𝜆n = 𝜆α
66. A
C
D
B
27 June - shift 1
2022
𝜆0
An electron (mass m) with an initial velocity
is moving in an electric field where E0 is constant. If at
t = 0 de Broglie wavelength is then its de Broglie
wavelength after time t is given by
𝜆0t
67.
68. A
C
D
B
27 June - shift 1
2022
𝜆0
𝜆0t
An electron (mass m) with an initial velocity
is moving in an electric field where E0 is constant. If at
t = 0 de Broglie wavelength is then its de Broglie
wavelength after time t is given by
69.
70.
71.
72.
73.
74.
75.
76. 29 June - shift 1
2022
are the impact parameters corresponding to
scattering angles 60° and 90° respectively, when an α particle is
approaching a gold nucleus. For d1 = xd2, the value of x will be _____ .
77. 29 June - shift 1
2022
are the impact parameters corresponding to
scattering angles 60° and 90° respectively, when an α particle is
approaching a gold nucleus. For d1 = xd2, the value of x will be _3__ .
78. A
C
D
B
25 July - shift 1
2022
The momentum of an electron revolving in nth orbit is given by:
(Symbols have their usual meanings)
79.
80. A
C
D
B
25 July - shift 1
2022
The momentum of an electron revolving in nth orbit is given by:
(Symbols have their usual meanings)
81. A
C
D
B
25 July - shift 2
2022
Hydrogen atom from excited state comes to the ground by emitting a
photon of wavelength 𝜆. The value of principal quantum number ‘n’ of
the excited state will be:
(R : Rydberg constant)
82.
83. A
C
D
B
25 July - shift 2
2022
Hydrogen atom from excited state comes to the ground by emitting a
photon of wavelength 𝜆. The value of principal quantum number ‘n’ of
the excited state will be:
(R : Rydberg constant)
84. 25 July - shift 2
2022
is the ratio of energies of photons produced due to transition
of an electron of hydrogen atom from its
(i) Third permitted energy level to the second level and
(ii) the highest permitted energy level to the second permitted level.
The value of x will be
85.
86. 25 July - shift 2
2022
is the ratio of energies of photons produced due to transition
of an electron of hydrogen atom from its
(i) Third permitted energy level to the second level and
(ii) the highest permitted energy level to the second permitted level.
The value of x will be _5_
87. 26 July - shift 1
2022
In a hydrogen spectrum, 𝜆 be the wavelength of first transition line of
Lyman series. The wavelength difference will be “a𝜆” between the
wavelength of 3rd transition line of Paschen series and that of 2nd
transition line of Balmer Series where a = ___
88.
89. 26 July - shift 1
2022
In a hydrogen spectrum, 𝜆 be the wavelength of first transition line of
Lyman series. The wavelength difference will be “a𝜆” between the
wavelength of 3rd transition line of Paschen series and that of 2nd
transition line of Balmer Series where a = _5_
90.
91.
92.
93.
94.
95.
96.
97.
98.
99.
100.
101.
102. A
C
D
B
26 June - shift 2
2022
4 : 3
Mass numbers of two nuclei are in the ratio of 4 : 3. Their nuclear
densities will be in the ratio of
1 : 1
103. A
C
D
B
26 June - shift 2
2022
4 : 3
Mass numbers of two nuclei are in the ratio of 4 : 3. Their nuclear
densities will be in the ratio of
1 : 1
104. A
C
D
B
27 July - shift 1
2022
9.5 tears
What is the half-life period of a radioactive material if its activity
drops to 1/16th of its initial value in 30 years ?
8.5 years
7.5 years
10.5 years
105.
106. A
C
D
B
27 July - shift 1
2022
9.5 tears
What is the half-life period of a radioactive material if its activity
drops to 1/16th of its initial value in 30 years ?
8.5 years
7.5 years
10.5 years
107. A
C
D
B
28 July - shift 1
2022
120 days
The half life period of a radioactive substance is 60 days. The time
taken for ⅞ th of its original mass to disintegrate will be:
130 days
180 days
20 days
108.
109. A
C
D
B
28 July - shift 1
2022
120 days
The half life period of a radioactive substance is 60 days. The time
taken for ⅞ th of its original mass to disintegrate will be:
130 days
180 days
20 days
110. 28 July - shift 1
2022
A freshly prepared radioactive source of half life 2 hours 30 minutes
emits radiation which is 64 times the permissible safe level. The
minimum time, after which it would be possible to work safely with
source, will be ______ hours.
111.
112. 28 July - shift 1
2022
A freshly prepared radioactive source of half life 2 hours 30 minutes
emits radiation which is 64 times the permissible safe level. The
minimum time, after which it would be possible to work safely with
source, will be _15_ hours.
113. A
C
D
B
26 June - shift 2
2022
3.75 hours
A radioactive nucleus can decay by two different processes. Half-life
for the first process is 3.0 hours while it is 4.5 hours for the second
process. The effective half-life of the nucleus will be:
0.56 hours
0.26 hours
1.80 hours
114.
115. A
C
D
B
26 June - shift 2
2022
3.75 hours
A radioactive nucleus can decay by two different processes. Half-life
for the first process is 3.0 hours while it is 4.5 hours for the second
process. The effective half-life of the nucleus will be:
0.56 hours
0.26 hours
1.80 hours
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