chỉ cần ôn 7 đề này chắc chắn sẽ trên 9đ môn vật lý 2 hoặc sẽ giúp bạn qua môn 1 cách dễ dàng mà không cần ôn luyện quá nhiều, tài liệu này là tài liệu trong danh sách ngân hàng đề thi của đại học Bách Khoa
NATIONAL UNIVERSITY – HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY FINAL EXAM OF PHYSICS A2 SEMESTER 1, YEAR 2015-2016 Closed book exam – Duration: 120 Code: 138 DEPARTMENT OF ENGINEERING PHYSICS Student’s name:……………………………………… Signature of Lecturer: ……………………………… Student ID: ……………………………………………… Signature of Dean: …………………………………… 01 ; / = ~ 06 ; / = ~ 11 ; / = ~ 16 ; / = ~ 02 ; / = ~ 07 ; / = ~ 12 ; / = ~ 17 ; / = ~ 03 ; / = ~ 08 ; / = ~ 13 ; / = ~ 18 ; / = ~ 04 ; / = ~ 09 ; / = ~ 14 ; / = ~ 19 ; / = ~ 05 ; / = ~ 10 ; / = ~ 15 ; / = ~ 20 ; / = ~ PART MULTIPLE CHOICE QUESTIONS Question In the Zeeman effect, the following selection rules are applied: A 1; m 1 B 1; m 0,1 C 1; m 1 D 1; m 0,1 Question In order of increasing strength the four basic interactions are: A gravitational, weak, electromagnetic, and strong B weak, gravitational, electromagnetic, and strong C weak, electromagnetic, gravitational, and strong D gravitational, electromagnetic, weak, and strong Question For valence electrons in atoms of sodium Na (Z=11), while taking into account of the spin, electrons can make the transition to energy level 32 D3 / from the following energy levels: A n 2P1/ (n 4,5,6 ); n 2P3 / (n 4,5,6 );n 2F7 / (n 4,5,6 ) B n P1/ (n 4,5,6 );n P3 / (n 4,5,6 );n F5 / (n 3,5,6 ) 2 C n P1/ (n 4,5,6 );n P3 / (n 4,5,6 );n F5 / (n 4,5,6 ) 2 D n P1/ (n 4,5,6 );n P3 / (n 4,5,6 );n F7 / (n 3,5,6 ) Question Electromagnetic radiation with a wavelength of 5.7×10 −12 m is incident on stationary electrons Radiation that has a wavelength of 6.57×10−12 m is detected at a scattering angle of: A 50◦ B 25◦ C 40◦ D 69◦ Question A particle in an infinite potential energy well of width a The particle is at the state of n=5 The probability of finding particle in the region [a/10, 4a/5] is: A 0.8 B 0.4 C 0.3 D 0.7 Question When a hydrogen atom makes the transition from the third excited state to the ground state (at−13.6 eV) the energy of the photon emitted is: A 9.1eV B 1.5eV C 12.1eV D 12.75eV 65 Question Given Ro=1.2fm The radius of 29 Cu nucleus is : A 4.8 fm B 3.8 fm C 5.8 fm D 6.8 fm Question The quark content of a proton is: Code 138 / Page of A uud B ddd C uuu D udd Question A particle is confined by finite potential energy walls to a one-dimensional trap from x=0 to x=L Its wave function in the region x λp C λe = λp 13 An electron is in a quantum state for which there are allowed values of the z component of the angular momentum The magnitude of the angular momentum A √3ħ B √6ħ C √5ħ D √12ħ 14 A radioactive source has a half-life of 100 days If the initial activity is 1.0 mCi, what is the activity after 30 days? A 0.14 mCi B 0.81 mCi C 0.55 mCi D 0.76 mCi 15 Protons in the nucleus attract electrons with enough electromagnetic force to keep them in orbit at high speeds Protons in general repel each other, but in the nucleus they are bound together Why ? A The strong force binds the protons together on small distance scales B The electrons orbiting the nucleus create an EM force on all sides due to their high speed of revolution C The electroweak force binds the protons together on small distance scales D The gravitational force binds the protons together on small distance scales 16 An alien spacecraft is flying overhead at a great distance as you stand in your backyard You see its searchlight blink on for 0.19s The first officer on the spacecraft measures that the searchlight is on for 12ms What is the speed of the spacecraft relative to the earth expressed as a fraction of the speed of light c? A 12c B 0.19c C 0.998c D none of these 17 The electron makes a transition from the n = to n = level by absorbing a photon Calculate the wavelength of this photon A 1024nm B 190nm C 486nm D 364nm 18 The wave function of one particle moving along Ox axis is showed in Figure below The wave function ψ(x) = with x ≤ and x ≥ Calculate the probability for finding this particle in the area ≤ x ≤ 5? A 50.5 % B 62.5 % C 25.5 % D 12.5 % 19 In Compton effect, the maximum kinetic energy of the emitted electrons is keV What's the wavelength of the incident light? A 0.3 Ǻ B 0.5 Ǻ C 0.6 Ǻ D 0.4 Ǻ 20 An electron has energy of 15 eV Define its frequency and the de Broglie wavelength A 2.4 x 1015 Hz, 3.9 x 10-10 m B x 1010 Hz, x 10-12 m 15 C 3.62 x 10 Hz, 0.317 x 10-9 m D No correct answer B PROBLEMS (L.O.1, L.O.2): (6 POINTS) Energy radiated per second from cm2 of the surface of a black-body is 36.75x103 J Calculate: a) The temperature of the body 2/2 b) The wavelength of the radiation emitted with the greatest intensity Ans: T=6000K; Wavelength= 483 nm An atom in a 3d state emits a photon of wavelength 475nm when it decays to a 2p state (a) What is the energy (in eV) of the photon emitted in this transition? (b) Find the number of allowed transitions if the atom is now in an external magnetic field of 3,5T Ignore the effects of the electron’s spin (c) Calculate the photon energies (in eV) emitted in the case (b) Given Bohr magneton µB= 9.27x10-24 J/T Ans: a 2,612eV; b transitions; c (2.612 – 0.0002)eV; 2.612 eV; (2.612 + 0.0002)eV The common isotope of uranium, 238U, has a half-life of 4.47x109 years, decaying to alpha emission (a) What is the decay constant? (b) What mass of uranium is required for an activity of 1.00 Ci? (c) How many alpha particles are emitted per second by 10.0 g of uranium? Ans: λ=4.92x10-18, m=2.99x103kg, λN=1.24x105 Some useful constants: h = 6,625.10 −34 J s σ = 5,67.10 −8 Wm −2 K −4 me = 9,1.10 −31 kg e = 1,6.10 −19 C b = 2,898.10 −3 mK 1Ci = 3.7x1010 decays/s 3/2 c = 3.10 m / s 234 Th by 4/2 5/2 National University – Ho Chi Minh City University of Technology Department of Engineering Physics FINAL EXAM OF PHYSICS A2 2018-2019 Closed book exam – Duration: 90 Student’s name: No Student ID: A) (L.O.1, L.O.2) MCQ ANSWER SHEET (4 pts): Choose for each question only one correct answer and darken corresponding circle in the following answer sheet A O O O O O B O O O O O C O O O O O D O O O O O 10 A O O O O O B O O O O O C O O O O O D O O O O O 11 12 13 14 15 A O O O O O B O O O O O C O O O O O D O O O O O 16 17 18 19 20 A O O O O O B O O O O O C O O O O O D O O O O O Einstein’s Postulates state that … A The laws of physics are the same in all inertial frames of reference B The speed of light in vacuum is the same in all inertial frames of reference and is independent of the motion of the source C A particle can travel at the speed of light in vacuum D Both A and B Planck assumed: A Energy can only be absorbed or released in tiny discrete packets, which are an integer multiple of a quantum energy B Quantum energy ε of an electromagnetic wave of wavelength λ is defined by the formula ε = hc / λ , where h is Plank constant and c is the speed of light in vacuum C Both A and B D None of these An alpha particle (m = 6.64 x10-27 kg) emitted in the radioactive decay of uranium-238 has an energy of 4.20 MeV What is its de Broglie wavelength? A 7.02 x10-15m B 5.67 x10-15m C 1.67 x10-15m D 7.20 x10-15m An electron in an atom initially has an energy of -3.2 eV above the ground state energy It drops to a state with an energy of -5.5 eV above the ground state energy and emits a photon in the process The momentum of the photon is: A 1.2 x 10-27 kg.m/s B 1.7 x 10-27 kg.m/s C 4.3 x 10-27 kg.m/s D 2.3 x 10-27 kg.m/s There are Uranium and Lead atoms in Uranium ore Lead atoms are the products of the radiation of Uranium The half life of Uranium is 5.5×109 years How old is the ore if the ratio between the number of Uranium and Lead atoms are 5:1: A.1.45 x 109 years B 4.47 x 109 years 6.02 x 108 years 8.02 x 1018 years Einstein suggested that: A Light is composed of tiny particles called protons B The speed of photon is c = 3.108 m/s in free space and equal v = c/n in medium C Each photon has energy ε = hc / λ , where h: Planck’s constant, λ : light wavelength D All of the above The wave function of a particle must satisfy certain feratures: A Must be a single-valued function B Must be normalizable C Must be a continuous function and the first derivative also must be continuous share the energy equally, and taking their masses to be 1.00 u, calculate their speeds after the photodisintegration Revision for Final exam 2020-2021 Nuclear physics A sample of rock from the Moon was verified The ratio between the number of Ar 40 nuclei and the number of K 40 was 10.3 Ar 40 is known as the product nucleus of the K 40 nuclear radioactivity Half life of K 40 is 1.25.109 year How old is this rock sample? From the following information calculate the minimum energy required to separate a deuteron into its component parts (1 amu = 931.2 MeV) Particle amu Proton 1.00727 Neutron 1.00866 Deuteron 2.0135 A 1.875 MeV C 2.26MeV B 2.02 MeV D 2.38 MeV E 4.03 MeV After the radiation of Pion (at rest initially), nuclei: Muyon and Neutrino are collected 𝜋 + → 𝜇+ + 𝜗 The rest energy of Pion and Muyon is 139.5 MeV; 105.7 MeV, respectively The total kinetic energy of the product nuclei is: a) b) c) d) 2.7×10-12 J 5.4×10-12 J 1.6×10-13 J 3.39×10-12 J Atomic physics An electron is in a quantum state for which the magnitude of the orbital angular momentum is √42ħ How many allowed values of z component of the angular momentum are there? In Hydrogen atom, electron is in 4p of level energy When this electron drops to the ground state, define the change of magnitude of magnetic dipole moment AW: -13.10-24 J/T 41.62/1403 Quantum Mechanics +Wave particle duality 6/An electron sits in the 2nd energy level in an infinite 1-D well The well is 10-12m wide What’s the electron’s kinetic energy? If the well were made double as wide as in the preceding problem, by what factor would the kinetic energy change? 7/ A proton is trapped in a quantum wire that is nm long (approximate a quantum wire is a 1D infinite potential well of width nm) What would be its de Broglie wavelength in the ground state? 8/An electron drops from the n=8 to the n=5 level of an infinite square well that is 2.10-12 m wide What is the wavelength of the photon emitted as a result? +Particle in a box 9/ Quantum Optics +Continuous spectra 10/A brick house has 1000 m2 of total area, the radiation temperature is 270C What is the radiated energy of this house during a day? Assume this house as a black body 11/A black body has 105 kW of radiation power If the wavelength related to the greatest radiation intensity is 7.10-7 m, what is the area of the body? +Compton scattering 12/ Electromagnetic radiation with 0.8 MeV of energy is scattered from stationary electrons The scatterd photons have wavelength equal to Compton wavelength Through what angle were the photons scattered? AW: 500 13/ X-rays with an energy of 450 keV undergo Compton scattering from a target If the scattered rays are deflected at 280 relative to the direction of the incident rays, find (a) the Compton shift at this angle, (b) the energy of the scattered x-rays, and (c) the kinetic energy of the recoiling electron (Compton wavelength is 2.43×10-12 m ) 14/ Electromagnetic radiation with a wavelength of 0,03.10-10 m is scattered from stationary electrons With scattered angle 600, 900, define the energy that transfers to electrons AW: 120 keV, 186 keV 15/ Electromagnetic radiation with a wavelength of 0,03.10-10 m is scattered from stationary electrons and photons that have been scattered through 900 are detected After the scattering event, what is the magnitude of the electron’s momentum? What is an angle of moving out electron? Special relativity 16/ A rod has a proper length of 2m It is moving with speed 0.8c with respect to a laboratory It also makes an angle 30 degree relative to the direction of moving Define the length of the rod in the laboratory frame Which phenomenon is best explained by the particle nature of light? A The Doppler Effect B Polarization C The photoelectric effect D interference According to the quantum theory of light, the energy of light is carried in discrete units called A alpha particles B photoelectrons C protons D photons If the wave properties of a particle are difficult to observe, it is probably due to the particle's A small size particle nature -> \delta x must be small, B large mass \delta p must be large C low momentum wave properties -> \delta p must be small, \delta x must be large D high charge If an orbiting electron falls to a lower orbit, the total energy of that atom will A remain the same conservation of energy, range is the atom itself B increase -> E decreases as the C decrease electron gets to lower energy state The energy of a photon varies directly with its A frequency B wavelength C speed D rest mass Blue light has a frequency of approximately 6.0 x 10^14 Hz A photon of blue light will have an energy of A 5.0 x 10^ -7 J B 4.0 x 10^ -19 J C 1.1 x 10^ -48 J D 6.0 x 10^ -34 J Protons in the nucleus attract electrons with enough electromagnetic force to keep them in orbit at high speeds Protons in general repel each other, but in the nucleus they are bound together How is this possible? a The strong force binds the protons together on small distance scales b The electrons orbiting the nucleus create an electromagnetic force on all sides due to their high speed of revolution c The electroweak force binds the protons together on small distance scales d The introduction of neutrons diffuses the protons' charge over a large volume e The gravitational force binds the protons together on small distance scales Scientists have made great strides towards unifying the fundamental forces of nature At the time of the publishing of the text, the most unified of theories shows that the total number of forces to be fundamental in physics is: a b c d e Electromagetism, gravitation, strong force, weak force An electron in a hydrogen atom drops from the n=3 energy level to the n=2 energy level The energy of the emitted photon is A B C D 4.91eV 1.51eV 1.89eV 3.40eV When an electron changes from a higher energy to a lower energy state within an atom, a quantum of energy is A fused B absorbed C emitted D fissioned Which electron transition in the hydrogen atom results in the emission of a photon of greatest energy? A n=3 to n=2 B n= to n=3 C n=4 to n=2 D n=2 to n=1 A photon having an energy of 15.5 eV is incident upon a hydrogen atom in the ground state The photon may be absorbed by the atom and A ionize the atom 15.5 > 13.6 the atom is B excite the atom to n=3 ionized C excite the atom to n=2 D excite the atom to n=4 The absorption of a photon causes a hydrogen atom to change from the n=2 to the n=3 energy state What is the energy of the absorbed photon? A B C D 3.4eV 4.9eV 1.9eV 10.2eV What is the minimum amount of energy required to ionize a hydrogen atom in the n=2 state? A B C D 13.6eV 10.2eV 3.4eV 0eV What alpha-particle scattering experiments indicate about an atom's structure? A Positive and negative charges are evenly distributed B Positive charge is concentrated in a small, dense core C Negative charge fills the space around the core D Electrons occupy distinct energy levels The term "electron cloud" refers to the A cathode rays in a gas discharge tube B high-probability region for an electron in an atom C negatively charged cloud that can produce a lightning strike D electron plasma surrounding a hot wire Which statement most accurately describes the interaction which binds a nucleus together? A short-range and weak B long-range and strong C long-range and weak D short-range and strong What is the force which holds the nucleons of an atom together? A magnetic force B nuclear force atomic is different from C coulomb force nuclear D atomic force Which particle would generate the greatest amount of energy if its entire mass were converted into energy? A electron B neutron C proton D alpha particle Approximately how much energy is produced when 0.50 atomic mass unit is completely converted into energy? A 9.3 x 10 ^ MeV B 4.7 MeV C 9.3 Mev D 4.7 x 10 ^ MeV A free electron and a free proton have the same momentum This means that, compared to the matter wave associated with the proton, the matter wave associated with the electron: A has a shorter wavelength and a greater frequency B has a longer wavelength and a greater frequency C has the same wavelength and the same frequency D has the same wavelength and a greater frequency E has the same wavelength and a smaller frequency The frequency and wavelength of the matter wave associated with a 10-eV free electron are: A 1.5 × 1034 Hz, 3.9 × 10−10 m B 1.5 × 1034 Hz, 1.3 × 10−34 m C 2.4 × 1015 Hz, 1.2 × 10−9 m D 2.4 × 1015 Hz, 3.9 × 10−10 m E 4.8 × 1015 Hz, 1.9 × 10−10 m The significance of |ψ|2 is: A probability B energy C probability density Probability = D energy density E wavelength Probability density The uncertainty in position of an electron in a certain state is 5×10−10 m The uncertainty in its momentum might be: A 5.0 ì 1024 kg ã m/s planck's constant, B 4.0 ì 1024 kg ã m/s rationalized 24 C 3.0 ì 10 kg ã m/s D all of the above E none of the above An electron with energy E is incident on a potential energy barrier of height Epot and thickness L The probability of tunneling increases if: A E decreases without any other changes B Epot increases without any other changes C L decreases without any other changes D E and Epot increase by the same amount E E and Epot decrease by the same amount The ground state energy of an electron in a one-dimensional trap with zero potential energy in the interior and infinite potential energy at the walls is 2.0 eV If the width of the well is doubled, the ground state energy will be: A 0.5 eV B 1.0 eV C 2.0 eV D 4.0 eV E 8.0 eV An electron is in a one-dimensional trap with zero potential energy in the interior and infinite potential energy at the walls The ratio E3/E1 of the energy for n = to that for n = is: A 1/3 B 1/9 C 3/1 D 9/1 E 1/1 An electron is in a one-dimensional trap with zero potential energy in the interior and infinite potential energy at the walls A graph of its probability density P(x) versus x is shown The value of the quantum number n is: A B C D E Given a graph of probability density > number of trough = quantum number An electron is trapped in a deep well with a width of 0.3 nm If it is in the state with quantum number n = its kinetic energy is: A 6.0 × 10−28 J B 1.8 × 10−27 J C 6.7 × 10−19 J D 2.0 × 10−18 J E 6.0 × 10−18 J The quantum number n is most closely associated with what property of the electron in a hydrogen atom? A Energy B Orbital angular momentum C Spin angular momentum D Magnetic moment E z component of angular momentum Take the potential energy of a hydrogen atom to be zero for infinite separation of the electron and proton Then the ground state energy is −13.6 eV The negative sign indicates: A the kinetic energy is negative B the potential energy is positive C the electron might escape from the atom Set the potential energy at infinity is Any energy state lower than infinity will have a negative sign D the electron and proton are bound together E none of the above (Quora) I think you're referring to -ve electron energy It means electron is bound to nucleus However,if we supply that much +ve energy to that electron it will come out of nucleus The Balmer series of hydrogen is important because it: A is the only one for which the quantum theory can be used B is the only series that occurs for hydrogen C is in the visible region red, cyan (turquoise), D involves the lowest possible quantum number n indigo, violet E involves the highest possible quantum number n Which of the following sets of quantum numbers is possible for an electron in a hydrogen atom? A n = 4, l = 3, ml = −3 B n = 4, l = 4, ml = −2 l