医学物理历年试题TestPaper02Aa

Medical College of Shantou UniversityThe Test Paper of Medical Physics for 2002 Imaging Class (A)Names:___________; Registration No:____________; Total Score:_________A. Multiple choice problems (3 marks for each correct answer)1. Four physical quantities, length, mass, time and temperature are frequently used inphysics. The standard units used in physics are called International System of Units (SI). The correct units used for length, mass, time and temperature in SI are _____respectively. (a) meter, gram, second and Kelvin,(b) meter, kilogram, second and Kelvin,(c) meter, kilogram, hour and Mole,(d) meter, gram, second and candela.2. If a spaceship moves with a speed of 0.8c (c is light speed) and in a very stronggravitational field, the theories of _______ should be used to describe the phenomena that occur in the spaceship.(a) Newton 's laws and special relativity(b) Quantum mechanics and special relativity(c) General relativity and quantum mechanics(d) Special relativity and general relativity3. When the ideal fluid flows steadily in a horizontal pipe, the relations of the cross-sectionS of the pipe, the velocity v of the fluid and the pressure p of the fluid is that ______. (a) Big S corresponds to small v and small p (b) Big S corresponds to big v and big p(c) Small S corresponds to big v and small p(d) Small S corresponds to small v and big p4. A particle moves in two SHMs that have the same vibrational direction and samefrequency. The equations of the two SHMs are given by()()cm t s cm t s πωπω-=+=cos 10,cos 321The amplitude of the additional (superposition) vibration is _____.(a) 3 cm (b) 13 cm (c) 7 cm (d) 10 cm5. Which one of the following is an absolute blackbody? Answer: ______(a) The body that does not radiate visible light.(b) The body that does not radiate any electromagnetic waves.(c) The body that does not receive visible light.(d) The body that does not receive any electromagnetic waves.(e) None of the above6. Light is a kind of electromagnetic waves and it has the wave property of interference. Iftwo beams of light interfere at a particular point in the space, what conditions should the two lights have at the meeting point? Answer: _____(a) Same frequency, same propagating direction. (b) Same frequency, same direction and the same initial phase.(c) Same frequency, same vibrational direction and a constant phase difference.(d) Same frequency and the same initial phase.7. If an object is located 8cm in front of a lens with focal length 10cm, then you can have______.(a) an upside-down (倒立的), reduced (缩小的) real image (b) an upside-down, magnified (放大的) real image(c) an upright, magnified virtual image(d) an upright, reduced virtual image8. There are 100 cars in a motor match. If all the motors produce 100 db noise level, what isthe sound intensity level produced by one car at the same time. Answer: ______.(a) 1 db (b) 200db (c) 15db (d) 80db. (e) None of the above9. If the magnitude of a wave function, which is a solution of Schrödinger equation, isdoubled at every point in the space, then the distributional probability of the particle in the space will ______.(a) Increase twice(b) Decrease twice(c) Increase four times(d) Be unchanged10. The hardness of x-rays depends only on the ____ of x-ray photon.(a) intensity (b) speed (c) number (d) energy11. Laser is very useful in medical science. Give your best choice for the production of laser.Answer _____.(a) You need to make the absorption, spontaneous emission and stimulated emission. (b) You need to make the population inversion and the spontaneous emission.(c) You need to make the spontaneous emission and stimulated emission.(d) You need to make the population inversion and stimulated emission.12. There are two kinds of nuclides (核素). One is stable and the other is radioactive. Theradioactive nuclides are not stable nuclei and they will decay. There are three classes of decays. One of them is β decay that also has three forms. A student writes the three equations to describe the three types of β decays asPlease give your equations to describe the three kinds of β decays.captureelectron decay Q decay Q A Z AZ A Z AZA Z AZQ Y X Y X Y X 1-1-1++→++++→+++→+++---νββνββνβ13.Two Styrofoam (泡沫聚苯乙烯) spheres of radii R1and R2, R1>R2, are releasedsimultaneously from the roof of a 60m high building.(a)Sphere 2 will arrive at the ground first.(b)Sphere 1 will arrive at the ground first(c)Both Spheres will reach the ground at the same moment.(d)The answer depends on the local atmospheric pressure.14.A lens made from glass with a refractive index of 3/2 is put in water that has a refractiveindex of 4/3. The focal length of the optical system is ______ if the lens has two convex surfaces with radii of curvature 0.1 m and 0.2 m respectively.(a)15/8,(b)15/2;(c)8/15;(d)2/15;(e)None of the above.B. Filling in the following blanks with your calculating results (3 marks for each blankin questions 1, 2 and 3; 1 mark for each blank in question 3):1. A myopic person has a far point of 0.5m and a near point of 0.1m . In order to correct the myopia, the power of the lens should be __200_____; when the person wears the corrective lenses, the new near point is ___0.125m____.2. William blows a soap bubble with diameter of 8cm. Suppose that its surface tension coefficient is 40 ⨯ 10-3 N m -1. The work done by blowing the soap bubble is _____ and the additional pressure in the bubble is __1Pa_____4pa.3. In an interference pattern from two slits, the tenth-order bright fringe is 40.0mm from the zeroth-order bright fringe. The double slit is 5 meters away from the screen, and the two slits are 0.5 mm apart. The wavelength of the light is _4*10-7_m_ and the spacing of the fifth and sixth bright fringes is _____4.0mm___.4. There are two coherent wave sources propagating in the same medium and in the same x-positive direction. Their motion can be described by the equations)(332cos 03.0)(32cos 05.021m x t S m x t S ⎥⎦⎤⎢⎣⎡+⎪⎭⎫ ⎝⎛-=⎥⎦⎤⎢⎣⎡+⎪⎭⎫ ⎝⎛-=ππππππ Obviously, these two waves will interference at any point on the x-axis.(1) The basic concepts:(a) the resultant equation of the superposition wave motion is:____________________;(b) its period is _________;(c) its wavelength is _________;(d) its amplitude is _________;(e) its angular frequency is _________;(f) the propagating speed of the wave is _________;(2) Based on the resultant wave equation you obtained in (1), at the position of x = 3 (m) and at the time of t = 3 (s):(a) the vibrational speed of the particle is _________;(b) the acceleration of the particle is _________;C. Calculating problems (Total marks :)1. (8 marks) An observer standing on the railway side hears a train moving away at thespeed of 40 m/s with a horn frequency of 680Hz. It is known that the velocity of sound is 340 m/s in air. Find(2) The original frequency of the horn on the train;(3) With the original frequency you found, calculate the frequency heard by another observer who runs after the train with a speed of 10 meters per second.Solution:2. (8 marks). A particle with mass 0.03kg moves around a circle of radius 0.4m . Supposethat its angular displacement can be described by a function of 22323++=t t θ (radian ). It is known that the positive angular velocity is for anti-clockwise rotation and negative angular velocity for clockwise rotation. Find:(a) its angular velocity at t = 5 second and its tangential speed at t = 2 second;(b) its angular acceleration at t = 5 second and tangential acceleration at t = 2 second; (c) the magnitude of its angular momentum to the center of the circle at t = 6 second; (d) the direction of the angular momentum if the circular motion is in x-y plane.Solution:3. (8 marks) Suppose that a particle is limited in a one dimensional, infinity deep potential well and its wave function and energy are given respectively by ⎪⎭⎫ ⎝⎛=a x n a n πψsin 2and mLh n E n 822= (0 < x < a ). In such a well for n = 2, find (1) the positions corresponding to the highest probabilities of finding the particle and with biggest value of ψ; (2) Calculate the De Broglie wavelength of the particle in such a state.Solution:4. (8 marks) (1). The extremes of x-ray portion of the electromagnetic spectrum range fromapproximately 1.0 ⨯ 10-8 m to 1.0 ⨯ 10-13 m. Find the minimum accelerating voltage requires to produce wavelength at these two extremes.(2). I n producing x-rays, the electrons are generally accelerated to a very high velocity u . if all the kinetic energy of an electron is transformed to a single x-ray photon that has a wavelength x λ. Prove that(a) Considering the relativistic effect, the velocity and the wavelength of x-rayshave the following relation:h c m h h c m c u x x ++=λλ0202where c is the light speed, h is Planck constant, m 0 is the rest mass of anelectron.(b) Without considering the relativistic effect, the relation between the de Broglie wavelength de λ of the electron and the wavelength x λof x-rays ismc h x de 2λλ=where m is the relativistic mass of the electron.Solution:5. (Re: Page 511, Physics, written by Kane & Sternheim, second edition) Lenses are madefrom glass with a refractive index of 1.5. (1) Find the focal length of the two lenses in air: (a) two convex surfaces with radii of curvature 0.1 m and 0.2 m respectively; (b) one plane surface and one curvature surface of radius 0.25 m; (2) If the two lenses in (1) (double-convex and plano-convex) are used in water with refractive index 4/3, find the corresponding focal lengths for them in this case.Medical College of Shantou UniversityThe Test Paper of Medical Physics for 2003 students under 7-year teaching system (A)Names:___________; Registration No:____________;C. Simple questions (2 mark for each question; total score 10)1. There are three kinds of strains which cause the changes of matter forms. What are they?2. Vectors C B A and ,are in one plane and the angle between C B and is 45︒. (1) What isthe obvious difference between )(C B A ⨯⨯ and )(C B A ⨯•? (2) If 222===C B A , Give your results for them respectively.3. Is the acceleration of a simple harmonic oscillator (振动器) ever zero? If so, where?Score4. What are the standard conditions for a wave function that is a solution of a Schrödingerequation?5. What are the coherent conditions for two mechanical waves?D. Right or wrong (2 mark for each question; total score 20)1. The object distance is always positive if the object is on the side of the lens from whichthe light is coming.right wrong2. Two steel spheres of radii R 1 and R 2 are put in a deep tank which contains viscous fluid,the one with bigger radius goes down slower than the other because the fluid is viscous.rightwrong 3. The hardness of x-rays depends only on the intensity of x-rays photon. right wrong4. The equations of the two SHMs are given by ()()cm t s cm t s πωπω-=+=cos 15,cos 1021as they are out of phase, the amplitude of the superposition vibration is 5 cm. right wrong5. As the molecules of surface-active agents tend to move to the inside of liquid, it cangreatly reduce the surface tension coefficient of the original liquid.right wrong6. The wavelength of the scattered light in Compton effect experiment becomes shorterbecause it lost some energy during the process of the collision with electron.right wrong7. When light travels through a medium with refractive index 1.5, its wavelength willbecome shorter and therefore its frequency will become higher in order to maintain the constant speed of light.rightwrong Score√8. The squared magnitude of a normalized wave function,2ψ, expresses the probability offinding the particle in the corresponding region. Therefore, if the wave function is multiplied by 2, the possibility of finding the particle in the same region should increase 4 times. right wrong9. The radioactive nuclides are not stable nuclei and they will decay. There are threeclasses of decays. One of them is β decay that also has three forms. A student writes the three equations to describe the three types of β decays asGive your answer choice:right wrong10. In Bohr’s theory, the quantized radius and energy of hydrogen are derived by thecondition (hypothesis) of angular momentum quantization and the stationary state condition.rightwrong E. Multiple choice problems (2 marks for each question, total score:24)15. Which one of the following is an absolute blackbody? Answer: ______a) The body that does not radiate visible light.b) The body that does not radiate any electromagnetic waves.c) The body that does not reflect visible light.d) body that does not reflect any electromagnetic waves.e) All of the above16. When the ideal fluid flows steadily in a horizontal pipe, the relations of the cross-sectionS of the pipe, the velocity v of the fluid and the pressure p of the fluid is that ______.a) S corresponds to small v and small pb) S corresponds to big v and big pc) Small S corresponds to big v and small pd) Small S corresponds to small v and big pe) None of the above17. The intensity of x-rays depends only on the ____ of x-ray photon.A. hardnessB. speedC. numberD. frequencyE. none of the above18. If an object is located 8 cm in front of a lens with focal length 10cm, then you can have Score: captureelectron decay Q decay Q A Z AZ A Z AZA Z AZQ Y X Y X Y X 1-1-1++→++++→+++→-++--+νββνββνβ______.a) reduced real image b) magnified (放大的) real imagec) magnified virtual imaged) reduced virtual imagee) none of the above19. Laser is very useful in medical science. Give your best choice for the production of laser.Answer _____.a) You need to make the absorption, spontaneous emission and stimulatedemission.b) You need to make the population inversion and the spontaneousemission.c) You need to make the spontaneous emission and stimulated emission.d) You need to make the population inversion and stimulated emission.20. The graph shows the amount of energy E radiated at a wavelength λ against thewavelength for different temperature. Which of following statements concerning the graph is TRUE? _________(1) T 1 > T 2 > T 3 (2) λ1 T 1 = λ2 T 2(3) λ1/λ2 = E 1/E 2a) (1) only,b) (2) only,c) (1) and (2), d) (1) and (3)21. The radii of the arms of a U-tube are respectively R 1 and R 2. A liquid of surface tensioncoefficient α (with angle of contact 0o ) is poured into the tube which is placed vertically. Find the difference in levels if P 0 is the atmospheric pressure. (P60,17)A. 10/2R P α-B. 210/4R R P α- D. ⎪⎪⎭⎫ ⎝⎛+21112R R g ρα 22.) (P58,10)A. 0 JB. 7.76 ⨯ 10-5 JC. 3.89 ⨯ 10-5 π JD. 7.76 ⨯ 10-5 π J23. Which of the following is NOT true concerning the emission of electron from a metalsurface by a suitable beam of light? ________a) Increasing the intensity of the beam will increase the number of photoelectron. λ3 λ2 λ1 λb) Only light of wavelength λ such that λ < λc (threshold wavelength) can causethe emission of electrons.c) Increasing the frequency of light will increase the maximum kinetic energy of the emitted electrons.d) Increasing the intensity of the beam will increase the velocity of the emittedelectrons. e) None of the above.24. A monochromatic light of wavelength 500nm falls on a double slit of separation 2mm. Ifa screen is placed at a distance of 3 m from the slits, find the separation between two dark fringes. _______A. 0.375mmB. 0.75cmC. 0.75 mmD.3.75 cm E. 6.3 mm25. An object is placed at a distance x from the focus of focal length f. the image formed is ata distance y from the focus. What is the relation between x, y and f? _____a)B. f y x y x 111=++-C. 2f xy =D. y xf =E. f xy =26. A particle with rest mass m 0 has a relativistic kinetic energy E k that is three times of itsrest energy. What is the correct relation between m and m 0? ________A. 02m m =B. 02m m =C. 04m m =D. 06m m =E. 03m m =F. Filling in the following blanks with your calculating results (3marks for each blank, total score 20)Planck constant: s eV s J h ⋅⨯=⋅⨯=--153410136.4 10626.6Light speed: m c 8100.3⨯=1. There are 100 cars in a motor match. If all the motors produce 100 db noise level, what isthe sound intensity level produced by one car at the same time. Answer: _ 80 db ___.2. A myopic person has a far point of 1.0m and a near point of 0.1m . In order to correct themyopia, the power of the lens should be _100___ diopter;Score3. A ruby laser emits light at 662.6 nm. If the energy released in each 10-11 second pulse is0.6 J, the number of photons in the pulse is _____________.4.if an x-ray machine has a cut-off wavelength of 0.0828nm, the electrical potentialdifference on the x-ray tube is at least __________.5. A lens made from glass with a refractive index of 3/2 is put in water that has a refractiveindex of 4/3. The focal length of the optical system is ______ if the lens has two convex surfaces with radii of curvature 0.1 m and 0.2 m respectively.6.William blows a soap bubble with diameter of 4cm. Suppose that its surface tensioncoefficient is 40 ⨯ 10-3 N m-1. The work done by blowing the soap bubble is _____ .7.There are two kinds of radioactive nuclides whose half-life are 8d and 6h respectively.Suppose that their radioactivities are the same, the radio of the two radioactive nuclide numbers is __32___.8.The wavelength of light in Compton effect experiment is 0.500000nm. The scatteredwavelength at a scattered angle of 900is _________. (Compton wavelength λc=0.00243nm)9.Ultraviolet light of wavelength 206.8 nm falls on a chromium electrode. The maximumkinetic energy of the photoelectron is _________ (the work function of chromium is 4.37 eV).10.A particle with mass m = 4.00 kg is in SHM at the end of a spring with spring constant k= 16.0 N/m. The initial displacement and velocity of the particle is 3m and 4.0 m/s respectively. The amplitude of the vibration is ________ (m).E. Calculating problems (Total marks: 16)2. (5 marks) An observer standing on the railway side hears a train horn with frequency680. But he knows that the horn frequency is 760. it is known that the velocity of sound is 340 m/s in air. Find the speed of the train.Solution:3. (6 marks) Suppose that a particle is limited in a one-dimensional infinity deep potentialwell and its wave function and energy are given respectively by ⎪⎭⎫ ⎝⎛=a x a πψ2sin 22 (0 < x < a ) and 2222ma h E =. Find (1) the positions corresponding to the highest probabilities of finding the particle and also with biggest value of ψ; (2) Calculate the De Broglie wavelength of the particle in such a state.Solution:Score(5 marks) A cylindrical water-tank has a very small hole 60cm above the floor on which the tank stands. The depth of water in the tank is 1.8m (see the figure). (1) Find the water-flow speed at the hole (Point B); (2) find the horizontal distance R from the side of the tank to the point on the floor where the stream of water lands. (hint: m h m h B A 6.0,8.1== and 0=A v .)Solution:Medical College of Shantou University The Test Paper of Medical Physics for 2004 students under 7-year teaching system (A)G. Answer the following questions (2 marks for each question; totalscore 10)6. What are the coherent （相干的） conditions for two mechanical waves?Score7. )cos(ϕω+=t A x is the equation of simple harmonic motion. Is the velocity of a simpleharmonic oscillator (振动器) ever zero? If so, where?8. There are three kinds of strains to describe the shape change of an object under differentstresses (forces). What are they?9. Surface tension coefficient α has two meanings. Give you explanations below.10. In Bohr ’s atomic theory, there are two hypotheses on orbital momentum and lightemissions. What are they? (hint: if you feel difficult in describing them by words, you could simply write their mathematical equations.)H. Right or wrong (2 marks for each question; total score 20) 11. The image distance is always positive if the image is on the side of the lens from whichthe light is coming.right wrong12. Two steel spheres of radii R 1 and R 2 are put in a very deep tank which contains viscousfluid, the one with bigger radius goes down faster than the other because the fluid is viscous.right wrong 13. The hardness of x-rays depends only on the energies of x-ray photons. right wrong14. The equations of the two SHMs are given by ()()cm t s cm t s πωπω-=+=cos 5,cos 321 as they are out-of phase (反相), the amplitude of the superposition vibration (21s s s +=) is |A 1 - A 2|, that is 2 cm .Score√ √√right wrong 15. As the molecules of non-surface-active agents tend to move to the surface of liquid, itcan change the surface tension coefficient of the original liquid greatly.rightwrong 16. The wavelength of the scattered light in the experiment of Compton effects becomeslonger because it lost some energy during the process of the collision with electron.right wrong17. When light travels through a medium with refractive index 1.5, both wavelength andfrequency of light will change a little bit in order to satisfy the speed of light in such a medium.right wrong 18. The squared magnitude of a normalized wave function,2ψ, expresses the probability offinding the particle in the corresponding region. Therefore, if the wave function ψ is multiplied by 3, the possibility of finding the particle in the same region should be 9 times larger.rightwrong 19. In damped harmonic motion, the system has the following properties due to the dampedforce exerting on the system: (1) the mechanical energy of the system decreases; (2) the vibrational amplitude decreases; (3) the period of the system decreases and (4) the vibration goes slower.right wrong .20. In the single-slit diffraction experiment, the center of bright fringes has to be satisfiedwith the condition of λθm a =sin . Where a is the width of the slit; m takes any integer numbers, λ is the wavelength used in the experiment.rightwrongI. Multiple choice problems (3 marks for each question, total score:30)(Note: None of the above means that no one of A, B, C and D is correct answer for the question)27. Planck ’s formula for blackbody radiation is given below:12)(/52-=-λλλπkT hc e hc T M Score: √√ √ √√ √ √in order to get Stefan and Boltzmann ’s law from above formula, you need at least ________.i. to ingrate M λ(T) with respect to λ;ii. to differentiate M λ(T) with respect to λ;iii. to make 1/<<λkT hc as it is valid when wavelength is large;iv. to make 1/>>λkT hc as it is valid when wavelength is small;28. When the ideal fluid flows steadily in a horizontal pipe, the relations of the cross-sectionS of the pipe, the velocity v of the fluid and the pressure p of the fluid is that ______.a) Big S corresponds to small v and small pb) Big S corresponds to big v and big pc) Small S corresponds to big v and small pd) Small S corresponds to big v and big pe) None of the above29. The intensity of x-rays depends only on the ____ of x-ray photons.A. hardnessB. speedC. numberD. frequencyE. none of the above30. If an object is located 12 cm in front of a thin lens with focal length 10cm, then you willhave a ______.a) reduced real imageb) magnified (放大的) real imagec) magnified virtual imaged) reduced virtual imagee) none of the above31. Laser is very useful in medical science. Give your best choice for the production of laser.Answer _____.a) You need to make the absorption, spontaneous emission and stimulatedemission.b) You need to make the population inversion and the spontaneousemission.c) You need to make the spontaneous emission and stimulated emission.d) You need to make the population inversion and stimulated emission.32. A monochromatic light of wavelength 600nm falls on a double slit of separation 2mm. Ifa screen is placed at a distance of 5 m from the slits, find the distance of the first bright fringe from the center of the zeroth order bright fringe. _______A. 0.3mmB. 0.15cmC. 0.15 mmD. 0.3cmE. 1.5 mm33. The graph shows the amount of energy E radiated from a blackbody at a wavelength λagainst the wavelength for different temperature. λi ( i = 1, 2, 3) are the wavelengths corresponding to the maximum energy of radiation for T 1, T 2, and T 3 respectively. Which(1) T 1 < T 2 < T 3(2) λ1 T 1 = λ2 T 2(3) λ1/λ2 = E 1/E 2a) (1) only, b) (2) only,c) (1) and (2),d) (1) and (3)34. Which of the following is NOT true concerning the emission of electron from a metalsurface by a suitable beam of light? ________a) Increasing the intensity of the beam will increase the number of photoelectrons. b) Only light of wavelength λ such that λ < λc (threshold wavelength) can causethe emission of electrons.c) Increasing the frequency of light will increase the maximum kinetic energy of the emitted electrons.d) Increasing the intensity of the beam will increase the velocity of the emittedelectrons.e) None of the above.35. A particle with rest mass m 0 has a relativistic kinetic energy E k that is three times of itsrest energy. What is the correct relation between m and m 0? ________A. 02m m =B. 02m m =C. 04m m =D. 06m m =E. 03m m =36. Find the energy released (释放了的) when eight identical rain drops of radius 1 cmcoalesce (combine) to form a single rain drop. (Surface tension coefficient of water = 7.0 ⨯ 10-2 Nm -1). ________A. 0 JB. 2.24 ⨯ 10-4 πJC. 1.12 ⨯ 10-4 JD. 1.12 ⨯ 10-4 π JE. Non of the aboveJ. Filling in the following blanks with your calculating results (4 marks for each blank, total score 32)Planck constant: h = 6.626×10-34 J ⋅s = 4.136×10-15 eV ⋅s Light speed: m c 8100.3⨯= Boltzmann constant: 1231038.1--⋅⨯=K J k ,1. A hyperopic (far-sighted) patient has a near point of 80 cm. In order to let him read thepaper of 20 cm in front of him, calculate the lens power required to remedy this defect. ____________2. There are 10 motorbikes in a motor match. If all the motors produce 10 db noise level,what is the sound intensity level produced by two motorbikes at the same time. ScoreAnswer:_________.3.Silicon has an atomic number of 14. That is Z = 14 for this atom. Write the ground-stateconfiguration for this atom (ground-state configuration of atoms is also called electronic configuration, or the distributions of electrons in atoms).__________________________.4.There are two kinds of radioactive nuclides whose half-life are 6 days and 12 hoursrespectively. Suppose that their radioactivities (also called radioactive intensity) are the same. At a particular moment, if the number of the latter (后者的) radioactive nuclide is 183⨯, the number of the former （前者）radioactive nuclide is _________________ 105.The wavelength of light in Compton Effect experiment is 0.500000nm. The scatteredwavelength at a scattered angle of 1800is _________. (Compton wavelength λc=0.00243nm)6.Ultraviolet light of wavelength 206.8 nm falls on a chromium electrode. The maximumkinetic energy of the photoelectron is _________ (the work function of chromium is 4.37 eV).7.In a medium, there is a particle in vibration. The period of this vibration is 2 secondswith its initial phase zero and amplitude 0.05 meters. This vibration propagates in the medium at a speed of 100m/s. Its wave equation in such a medium is ____________________.。