111年 - 111 國立清華大學學士後西醫學系單獨招生考試_學士後醫學系/自然科學組：物理#110533

科目：學士後西醫-物理 | 年份：111年 | 選擇題數：30 | 申論題數：0

試卷資訊

所屬科目：學士後西醫-物理

選擇題 (30)

31. Which of the following values is closest to the average translational kinetic energy of one mole of N2 gas at a temperature of 27℃? The Boltzmann constant is (A) 500 J(B) 1000 J (C) 2000 J (D) 4000 J (E) information is not sufficient to answer 
32. A 50-kg boy runs up the stairs to the top of the 200-m tall 18 Peaks Mountain in 8 minutes and 20 seconds. Which of the following values is closest to his average power output in horse power? (g = 10 m/s2 , 1 hp = 750 W) (A)0.4 (B)0.3  (C) 2.0(D) 10.0 (E) 50.0
33. A magnetron in a microwave oven emits electromagnetic waves with frequency f = 2450 MHz. Which of the following values in Gauss is closest to the magnetic field strength required for electrons to move in circular paths with this frequency? (A) 5 (B) 50 (C) 200(D) 600  (E) 900

34. Suppose two parallel plates in Fig. 4, cach has an area of 100 cm2and are 0.1 cm apart. The capacitor is connected to a power supply and charged to a potential difference V0 = 3000 V. It is then disconnected from the power supply. Which of the following values is closest to the total energy (U) stored in the capacitor in J?
(A)  (B) (C)(D)  (E)

35. A heat pump does work W to bring heat QL from the cold outside (at constant temperature TL) and deliver heat QH to warm the interior at constant temperature TH. Which of the following is wrong? (A) The coefficient of performance COP =(B) W= QH-QL(C) COP ＜1.0 (D) Ideally COP =(E) QH ＞QL 

36. Which of the following values is closest to the minimum power in hp required for a 1000-kg car that is climbing a 5.7° hill at a steady 72 km/h? Assume that the average drag force on the car at that speed is 500 N throughout. (g = 10 m/s2 , 1 hp = 750 W) (A) 5 (B) 20 (D) 100 (E) 300 (C) 40

37. Which of the following values is closest to the total electric potential energy of 1 mole of H2O? For simplicity in calculation, here we assume a pure ionic bonding (H carries a charge te； O, -2e), the O–H bond length ≅ 100 picometers, and the H–O–H bond angle is 180°. (A) 4.8 kJ/mol (B) 24 kJ/mol (C) 48 kJ/mol (D) 240 kJ/mol (E) 480 kJ/mol

38. Suppose an electron is trapped in a one-dimensional infinite well of width L = 2 nm: U = 0 from 0 to L, U =∞o everywhere else. Obviously the particle can never climb out of well. Which of the following values is closest to the energy of the photon (in eV) that emits when the electron make the transition from level n = 4 to n= 3. (h = 6.6✖m2kg/s； me = 9.1x10kg) (A) 0.02 (B) 0.06 (C)0.2 (D)0.6 (E) 2.0

39. A simple DC motor run by a 9.0 V battery has a 20 turn square coil with sides of length 5.0 cm and total resistance of 24Ω (Fig. 5). When the motor spins, the magnetic field felt by the wire in the coil is T. Which of the following values is closest to the the maximum torque on the motor in mㆍN?(A)(B) (C)  (D) (E)                 

40. A helicopter rotor blade can be considered as a long thin rod, as shown in Fig. 6. If each of the three-rotor helicopter blades is 3.75 m long and has a mass of m = 1.60 x 102 kg, which of the following value is closest to the moment of inertia of the three rotor blades about the axis of rotation in kg·m2?
(A) 5000 (B) 2000 (C) 1000 (D) 100(E) 20
41. Car A leaves point O at t = 0 and travels counterclockwisely along a quarter circle of radius 100 m at constant speed 30.0 m/s to reach point P. Car B is supposed to leave point O and travels to point P at the same speed but along a straight line. At what time should car B leave point O in order to arrive at point P at the same time as car A? (A)t=-4.71 s (B)t=-0.53s (C)t=0(D)t=0.53s (E)t=4.71s

42. In a one dimensional problem, an object of mass m = 2.0 kg is under effect of a resultant force Fxas shown in Fig. 7. If the object  passes through the origin (x = 0.0 m) with initial velocity v0 = -2.0 m/s at t = 0, what is the velocity at t = 4.0 s?

(A) -2.0 m/s (B) -3.0 m/s (C) -5.0 m/s (D) -8.0 m/s (E) -16.0 m/s

43. A spaceship of mass m circles a planet (mass = M) in an orbit of radius R. How much energy is required to transfer the spaceship to a circular orbit of radius 3R? (A) (B) (C) (D)(E)

44. Two blocks, m1 = 1.0 kg and m2 = 2.0 kg, are connected by a light string as shown in Fig. 8. The radius of the pulley is 0.2 m and its moment of inertia is 0.2 kg．m2 . If there is no slipping between the pulley and the string, what is the acceleration of block m1?
(A)g (B)g/2(C) g/3 (D)g/4 (E)g/8
45. A wave is transmitted along a string. Which of the following actions can quadruple the energy transmitted per unit time?
 I. double the frequency
 II. double the tension of the string
 III. double the amplitude
 IV. double the wave velocity
V. quadruple the frequency
 VI. quadruple the amplitude (A) III, V (B) II,Ⅲ, V (C) I, VI (D) I, III (E) I, II, III
46. An empty can and a full can of the same shape are rolled side-by-side down an incline without slipping. If they start together at the same height, which of the following statements is correct? (A) The empty can arrives at the bottom first. (B) The full can arrives at the bottom first. (C) They both will arrive at the bottom together because the gravity acceleration is the same. (D) It depends on the materials of the cans. (E) It depends on the incline angle.

47. An ideal gas is allowed to undergo a free expansion from volume V1 to volume V2. what is the change in entropy? (A) 0 (B) nRV2/V1 (C) nR(V2-V1) (D)(E)

48. There is a parallel-plate capacitor of capacitance C0. A slab of dielectric material with κ= 2 is placed into the gap between the plates, filling the bottom half of the gap. What is the resulting capacitance? (A) (B)(C) (D)2C0 (E) 3C0

49. Electromagnetic wave is travelling in the free space with the amplitudes of the electric and magnetic fields as Emax and Bmax, respectively. What is the average energy density in the space?  (A) (B) (C) (D)(E)
50. Which of the following observations in the photoelectric effect experiment can be explained by the wave behavior of light? (A) There is a cutoff frequency below which no photoelectric current can be observed. (B) Photoelectric current increases with increasing the intensity of the light. (C) There is a stopping potential for photoelectric current regardless the intensity of the light. (D) Dependence of ejection of electrons on light frequency. (E) Dependence of photoelectron kinetic energy on light frequency.

51. Two blocks of equal mass m placed on a frictionless flat surface are connected by a massless spring of a spring constant k, see Fig. 9. In the beginning, the spring is at its natural length, while the mass on the left is at rest and the mass on the right is moving towards right with a speed of v. The two-mass system would go on moving and oscillating relatively. During the oscillation, the maximum extension of the spring is L. What is the minimum value of the kinetic energy of the two-mass system during the oscillation?(A)(B)(C)(D)(E)

52. The simple harmonic motion is a general phenomenon that occurs as one perturbs a system at stable equilibrium slightly away from its potential minimum. Estimate the period of the simple harmonic motion for a particle of mass m experienced a potential energy of the form U(x) = a(1/x + b2x) (Joule) as the particle is slightly pushed away from , where x is the spatial coordinate of the (A) (B)  (C) (D) (E) 2π
53. Two strings of different linear mass density are joined at x = 0 to form a new string. The heavier string and the lighter string are on the left and right hand side of x = 0, respectively. Now, we keep the string stretched with a fixed weight, and send a wave from the heavier end to the lighter end. Which of the following statements is correct? (A) As the wave travels to the lighter end, its profile is amplified. (B) As the wave travels to the lighter end, its speed decreases. (C) As the wave hits x = 0, the reflected wave travels faster in the heavier string. (D) The speed of the traveling wave remains the same regardless of which ends. (E) As the wave hits x = 0, there is no reflected wave.
54. Two different gases of similar mass density at room temperature react differently as the pressure is varied. Specifically, as the external pressure is raised from l atm to 1.01 atm, the volume of gas A is reduced by 0.1% while the volume of gas B is reduced by 0.2%. Which of the following statements is true? (A) The sound speed of gas A is faster. (B) Low frequency sound waves travel faster than the high frequency ones in (C) Low frequency sound waves travel slower than the high frequency ones in gas A. (D) For the same sound source of frequency f, the frequency changes more as it enters gas B. (E) As we reduce the pressure, the volume of the gas does not al ways increase. gas A.
55. Two ambulances have identical sirens that would make sound waves of frequency 700 Hz. A stationary observer is in the straight line and in between these two ambulances, while one ambulance is parked and the other is moving away the observer. The observer notices that the combined sound wave exhibits a beat frequency of 20 Hz. What is the speed of the ambulance moving away from the observer? Take the speed of sound to be 340 m/s, and there is no wind blowing during the observation. (A) 5 m/s (B) 10 m/s (C) 12 m/s (D) 17 m/s (E) 18 m/s

56. Given a non-uniform charge distribution ρ(r)= alr (C/m3) between two concentric spheres of radius R and 2R, and it is enclosed by a thin metal spherical shell of radius 2R (negligible thickness) as shown in Fig. 10, what is the surface charge density on the inner surface of the metal shell?
(A) (B)(C) (D) (E)

57. A charging RC circuit consists of a battery with emf ε, a resistor R, and two capacitors C1 and C2 as shown in Fig. 11. The two capacitors are identical when there are no dielectrics inserted (that is C1 = C2= when placed in vacuum). In order to increase the capacitance, we place a dielectric material of the dielectric constant x in C2. At t = 0, there are no charges in capacitors, and we close the switch to charge these capacitors. Which of the following statements is correct?
  (A) The charging percentage () of these two capacitors would be the same at all times. (B) The maximum charges stored in these two capacitors would be the same. (C) The charging time would reduce if a larger resistor is used. (D) The charging time would reduce if a battery with a larger enf is used. (E) As more and more charges are stored in the capacitors, we expect the current flowing through the resistor is getting larger and larger.

58. A metal rod is pulled to the right in a uniform magnetic field so that it accelerates at a constant accelerationon rails and forms a closed circuit with a resistor R as shown in Fig. 12. For simplicity, let us say at t = 0, the metal rod coincides with the resistor at x = O and is at rest. The distance between rails is L. Assume that there is no friction between the rod and rails. Which of the following statements is correct?
(A) The emfinduced by pulling the Uniform magnetic field Boz metal rod is proportional to t2. (B) The force required to pull the metal rod is proportional to t. (C) The power dissipation in resistor is proportional to t3. (D) The work done by the pulling force is proportional to t. (E) None of the above is correct.
59. Which of the following statements about electromagnetic (EM) waves radiated from a point source with a fixed power is correct? (A) The amplitude of the electric field strength of the EM wave decays with distance squared. (B) The power received by a detector placed along the radial direction decays with distance. (C) The energy flux density decays with distance squared. (D) The larger the power radiated by the source is, the shorter the wavelength of the EM wave is. (E) The amplitude of the magnetic field strength of the EM wave does not depend on distance.

60. The PV curve for the van der Waals equation at a fixed temperature is plotted in Fig. 13. In this case, the liquid phase can coexist with the gas phase at pressure Pc. The pressure Pc intercepts with the PV curve at three points: a, c, and e, respectively. And the slope of the PV curve vanishes at b and d. Which of the following statements is correct?
(A) For pressure a bit higher than PC, it is impossible to have a stable gas phase. (B) For pressure a bit lower than  PC, the gas phase is more stable than the liquid phase. (C) The region a→ b is the supercooled liquid region. (D) The region b → c → d corresponds to a fluid with a positive compressibility. (E) None of the above.

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