【站僕】摩檸Morning>試卷(2020/04/01)

# 93 年 - 47學士後西醫普通物理學93普通物理學#84288

1.1. Light of wavelength 680 nm falls on two slits and produces an interference pattern in which the fourth-order fringe is 38 mm from the central fringe on a screen 2.0 m away. What is the separation of the two slits?
(A) 1.4×10−4m
(B) 2.1×10−4m
(C) 2.8×10−4m
(D) 4.2×10−4m
(E) 5.6×10−4m .

2.2. A long solenoid of 500 turns carrying a current of 3.8 A produces within itself a uniform magnetic flux of 2.0 mWb. What is the self-inductance of the coil?
(A) 0.13 H
(B) 0.26 H
(C) 0.36 H
(D) 0.46 H
(E) 0.52 H .

3.3. In a sinusoidal-ac circuit, the current is I=I0sin(ωt +θ) . What is the rms(root-mean-square) current ?
(A) I0
(B) I0 /1.414
(C) I0 /0.707
(D)πI0
(E) 2πI0.

4.4. A cylinder of mass 10.0 kg rolls without slipping on a horizontal surface. At the instant when its center of mass has a speed of 10.0 m/s, what is the cylinder’s total energy?
(A) 200 J
(B) 250 J
(C) 500 J
(D) 750 J
(E) 1000 J .

5.5. A sample of 770 mol of nitrogen gas is maintained at a constant pressure of 1.00 atm in a flexible container. The gas is heated from 40o C to 180o C. What is the change in internal energy?（ Cp=6.95 cal/mol·Co , R=8.315 J/mol·K）
(A) 3.32×104J
(B) 2.24×106J
(C) 6.22×106J
(D) 7.12×107J
(E) 8.82×107J .

6.6. A 1.00-kg mass is attached to a horizontal spring. The spring is initially stretched by 0.100 m and the mass is released from rest there. After 0.500 s, the speed of the mass is zero. What is the maximum speed of the mass?
(A) 0.326 m/s
(B) 0.438 m/s
(C) 0.510 m/s
(D) 0.593 m/s
(E) 0.628 m/s .

7.7. What is the absolute pressure at the bottom of a lake that is 30.0 m deep, when the air pressure is 1.0 atm?
(A) 4.32×103 Pa
(B) 6.65×104 Pa
(C) 2.36×105 Pa
(D) 3.95×105 Pa
(E) 4.89×105 Pa .

8.8. A magnetic field given by B（t）=0.2t - 0.5t2 T is directed perpendicular to the plane of a circular coil containing 25 turns of radius 1.8 cm and whose total resistance is 1.5Ω . What is the power dissipation at 3 s ?
(A) 2.28 mW
(B) 3.38 mW
(C) 4.52 mW
(D) 5.56 mW
(E) 6.72 mW .

9.

9. Suppose that the temperature at the center of the Sun is 2.00×107 K, what is the average translational kinetic energy of a proton in the Sun’s center? （kB=1.3810−23 × J/K）
(A) 1.38×10−16J
(B)4.14×10−16J
(C) 5.52×10−16
(D) 7.64×10−16
(E) 8.96 ×10−16J

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10.10. A nonconducting sphere of radius 10 cm has charge uniformly distributed throughout its volume. The electric field is directed radially outward and its strength at 5 cm from the center is 2000 N/C. What is the volume charge density of the sphere? (∈0 =8.85×10−12C2 /N·m 2 ）.
(A) 1.06 µC/m3
(B) 2.12 µC/m3
(C) 3.16 µC/m3
(D) 4.06 µC/m3
(E) 5.18 µC/m3.

11.11.When radiation of wavelength 350 nm is incident on a surface, the maximum kinetic energy of the photoelectrons is 1.2 eV. What is the stopping potential for a wavelength of 230 nm?（ h=6.63×10−34 J·s, qe = –1.60×10−19  C, c=3×108 m/s）
(A) 1.65 V
(B) 2.04 V
(C) 2.55 V
(D) 3.05 V
(E) 4.82 V .

12.12. An electron in the hydrogen atom makes a transition from the n=5 level to the n=2 level. What is the wavelength of the emitted photon? （qe = –1.60×10−19 C, h=6.63×10−34 J·s）
(A) 326 nm
(B) 435 nm
(C) 578 nm
(D) 662 nm
(E) 769 nm .

13.13. A proton is projected toward a fixed nucleus of charge +Ze with velocity V0 . Initially the two particles are very far apart.When the proton is at a distance R from the nucleus, its velocity has decreased to1/2 V0 .How far from the nucleus will the proton be when its velocity has dropped to1/4 V0
(A) 1/16 R
(B) 1/4 R
(C) 1/2 R
(D) 4/5 R
(E) 6/7 R .

14.14. An important observation that led Bohr to formulate his model of the hydrogen atom was the fact that .
(A) the emission of light by an atom did not appear to conserve energy.
(B) electrons were found to have a wave nature.
(C) the peak of the blackbody radiation moved to shorter wavelengths as the temperature was increased.
(D) neutrons formed a diffraction pattern when scattered from a nickel crystal.
(E) a low density gas emitted a series of sharp spectral lines. .

15.15. If the peak electric field in an electromagnetic wave is 1200 V/m , what is the peak magnetic field for the same wave?
(A)2.2×10−6
(B)3.4×10−6
(C)4.0 ×10−6T
(D)8.7×10−6
(E)9.6×10−6T.

16.16. The square plates of a 9000 pF capacitor measure 90 mm by 90 mm and are separated by a dielectric which is 0.29 mm thick. The voltage rating of the capacitor is 300 V. The dielectric strength of the dielectric, in kV/m , is closest to .
(A) 930
(B) 1000
(C) 1100
(D) 1200
(E) 1300 .

17.17. Electromagnetic standing waves are set up in a conducting cavity resonator in the form of a hollow metal box. The waves bounce back and forth between two parallel surfaces separated by 0.8 cm. What is the minimum resonant frequency for such a resonator?
(A) 3.30 GHz
(B) 4.42 GHz
(C) 12.4 GHz
(D) 15.5 GHz
(E) 18.8 GHz .

18.

18. The potential energy function of a particle moving in one dimension is U=kx2e−x2/a2where  a = 7.50nm . At what value of x is a point of stable equilibrium located?
(A) 6.81 nm
(B) 7.50 nm
(C) 7.80 nm
(D) 11.03 nm
(E) 12.62 nm

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19.19. A proton with speed  v = 3.00×105m/s orbits just outside a charged sphere. The radius of the orbit is 1.0 cm. What is the charge on the sphere? (The mass of a proton is 1.67×10−27kg.)
(A)1.04×10−9
(B)3.47×10−8
(C)6.23×10−8
(D)6.50×10−8
(E)8.28×10−7C.

20.20. A 1.0µF capacitor with an initial stored energy of 0.50 J is discharged through a 1.0 MΩ resistor. What is the current through the resistor when the discharge starts?
(A)1.0×10−3
(B)2.0×10−3A
(C)1.0×10−2A
(D)2.0×10−2A
(E)5.0×10−2A .

21.21. A hollow sphere of inner radius 8.0 cm and outer radius 9.0 cm floats half-submerged in a liquid of density 800kg/m3 . What is the density of the material of which the sphere is made?
(A)1.1×103kg/m3
(B)1.3×103kg/m3
(C)1.8×103kg/m3
(D)2.4×103kg/m3
(E)4.8×103kg/m3.

22.22. Three sinusoidal waves of the same frequency travel along a string in positive direction of an x axis. Their amplitudes are y1 ,y1/ 2and y1/3 , and their phase constants are 0, π/2, and π, respectively. What is the phase constant of resultant wave?
(A) 30°
(B) 37°
(C) 45°
(D) 53°
(E) 60° .

23.23. A girl is sitting near the open window of a train that is moving at a velocity 10.00m/s to the east. The girl’s uncle stands near the tracks and watches the train move away. The locomotive whistle emits sound at the frequency of 500.0 Hz. The air is still. What frequency does the uncle hear? (The speed of sound is 343m/s.)
(A) 471.7 Hz
(B) 485.8 Hz
(C) 500.0 Hz
(D) 515.0 Hz
(E) 530.0 Hz .

24.24. Two point charges q1=2.1×10-8C and q2 = −4q1 are fixed in two places 50 cm apart. The point charge  q1 is at the right side of  q2 . Find the point at which the electric field is zero, along the straight line passing through the two charges. The point is .
(A) 50 cm to the right of  q1
(B) 50 cm to the left of  q2
(C) 100 cm to the right of  q1
(D) 100 cm to the left of q2
(E) The middle point between  q1 and  q2.

25.25. A 5.0 g marble is fired vertically upward from a spring gun. The spring must be compressed 8.0 cm if the marble is to just reach a target 20 m above the marble’s position on the compressed spring. What is the spring constant of the spring?
(A) 1.6 N/cm
(B) 1.8 N/cm
(C) 2.5 N/cm
(D) 3.1 N/cm
(E) 6.2 N/cm .