医学物理历年试题

1、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 in physics. The s

2、tandard 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

3、 condela.2. If a spaceship moves with a speed of 0.8c (c is light speed) and in a very strong gravitational field, the theories of _ should be used to describe the phenomena that occur in the spaceship.(a) Newtons laws and special relativity(b) quantum mechanics and special relativity(c) general rel

4、ativity and quantum mechanics(d) special relativity and general relativity3. When the ideal fluid flows steadily in a horizontal pipe, the relations of the cross-section S 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 big p(b)

5、 Big S corresponds to big v and small p(c) Small S corresponds to big v and big p(d) Small S corresponds to small v and big p4. A particle moves in two SHMs that have the same vibrational direction and same frequency. The equations of the two SHMs are given by The amplitude of the additional (superp

6、osition) 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 reflect visible light.(d) The body th

7、at does not reflect any electromagnetic waves.6. Light is a kind of electromagnetic waves and it has the wave property of interference. If two 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, sam

8、e 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 12 cm in front of a lens with focal length 10cm, then you ca

9、n 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. If one motor produces 20db noises, what is the sound intensity level produced by 10 motors at the same time. Answer:

10、_.(a) 30db(b) 200db (c) 15db(d) 40db9. If the magnitude of a wave function, which is a solution of Schrdinger equation, is doubled 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 un

11、changed 10. 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 emissio

12、n.(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 radioactiv

13、e. The radioactive nuclides are not stable nuclei and they will decay. There are three classes of decays. One of them is b decay that also has three forms. A student writes the three equations to describe the three types of b decays asPlease give your equations to describe the three kinds of b decay

14、s.13. Two Styrofoam (泡沫聚苯乙烯) spheres of radii R1 and R2 , R1 R2, are released simultaneously 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

15、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 refractive index 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)

16、8/15;(d) 2/15;(e) none of the above.B. Filling in the following blanks with your calculating results (3 marks for each blank in 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

17、 the lens should be _-2D（_-200度）_; 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 pressur

18、e in the bubble is _2Pa_.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 _0.04mm_ and the spacing of the fif

19、th and sixth bright fringes is _4mm_.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 equationsObviously, these two waves will interference at any point on the x-axis. (1) The basic concepts:(a) the resul

20、tant 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 tim

21、e 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 the speed of 40 m/s with a horn frequency of 680Hz. It is known that the

22、 velocity of sound is 340 m/s in air. Find (2) the original frequency of the horn on the train;（780Hz）(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.（700Hz）Solution:2. (8 marks). A particle wi

23、th mass 0.03kg moves around a circle of radius 0.4m. Suppose that its angular displacement can be described by a function of (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

24、 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

25、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 and (0 x a). In such a well for n = 3, find (1) the positions corresponding to the highest probabilities of finding the

26、particle and with biggest value of y; (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 from approximately 1.0 10-8 m to 1.0 10-13 m. Find the minimum accelerating voltage requires to

27、 produce wavelength at these two extremes. (2).In 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 . Prove that (a)Considering the relativistic effect, the veloc

28、ity and the wavelength of x-rays have the following relation:where c is the light speed, h is Planck constant, m0 is the rest mass of an electron.(b) Without considering the relativistic effect, the relation between the de Broglie wavelength of the electron and the wavelength of x-rays is where m is

29、 the relativistic mass of the electron.Solution: Some exam problems in 20031. Is the acceleration of a simple harmonic oscillator (振动器) ever zero? If so, where?2. What are the standard conditions for a wave function that is a solution of a Schrdinger equation?3. Vectorsare in one plane and the angle

30、 between is 45. (1) What is the obvious difference between and? (2) If, Give your results for them respectively.4. What is the half-life?B Right or wrong1. The object distance is always positive if the object is on the side of the lens from which the light is coming. right wrong2. The radioactive nu

31、clides are not stable nuclei and they will decay. There are three classes of decays. One of them is b decay that also has three forms. A student writes the three equations to describe the three types of b decays asGive your answer choice: right wrong3. In Bohrs theory, the quantized radius and energ

32、y of hydrogen are derived only by the condition (hypothesis) of angular momentum quantization and the stationary state condition. right wrongC Multiple choice problems (2 marks for each question, total score: 24)hP0P015. The radii of the arms of a U-tube are respectively R1 and R2. A liquid of surfa

33、ce tension coefficient a (with angle of contact 0o) is poured into the tube which is placed vertically. Find the difference in levels if P0 is the atmospheric pressure. (P60,17)A. B. C. ,D.16. An object is placed at a distance x from the focus of focal length f. the image formed is at a distance y f

34、rom the focus. What is the relation between x, y and f? _a) B. C.D. E.Calculations:5. There are 100 cars in a motor match. If all the motors produce 100 db noise level, what is the sound intensity level produced by one car at the same time. Answer:_.6. A myopic person has a far point of 1.0m and a near point of 0.1m. In order to correct the myopia, the power of the lens should be _ diopter; 7. A ruby laser emits light at 662.6 nm. If the energy released in each 10-11 second pulse is 0.6 J, the number of photons in the pulse is _.