112年 - 112 台灣聯合大學系統_學士班轉學考試_A3/A6：普通物理#118471

科目：研究所、轉學考(插大)◆普通物理學 | 年份：112年 | 選擇題數：25 | 申論題數：0

試卷資訊

所屬科目：研究所、轉學考(插大)◆普通物理學

選擇題 (25)

1. A small coin is placed at the rim of a turntable of radius R which rotates at angular velocityω. What is the minimum coefficient of friction (μ min) for the coin to stay on? (A) Rω/2g ；(B) Rω2/ 2g ；(C)Rω2／g ；(D) R2ω/ g ；(E) None.

2. A pendulum of length L has its motion interrupted by a peg vertically beneath the support at a distance y below support, see Fig. 1. The bob is released when the string is horizontal.What is the minimum value of y for the bob to swing in a complete circle?
(A) L/2 ； (B) 2L/3； (C) 3L/4 ；(D) 3LI5；(E) None.
3. A rocket is fired vertically with half the "escape speed". (Ignore the earth's rotation) What is its maximum altitude in terms of the earth RE?(A) RE；(B) RE/2 ；(C) RE/3； (D) RE/4 ；(E) None.
4. How can a skydiver achieve a smaller "terminal speed"?(A) Reducing the effective cross-section； (B) Losing weight；(C) Diving in a diluted atmosphere； (D) All； (E) None.
5. What is not correct for a "conservative force"?(A) It can always be associated with a potential energy； (B) Its work done between two locations depends on the path taken； (C) It cannot be a function of velocity； (D) The total work done by it is O upon returning to the starting point； (E) None.
6. Which is correct for a downhill race among a loop, a cylinder, and a solid sphere (all with the same mass M and radius R) by rolling (with no slip)? (A) The loop is the loser； (B) The solid sphere is in the 2nd place； (C) The cylinder is the winner； (D) All； (E) None.

7. A block of density ρB has a horizontal cross-sectional area A and a vertical height h. It floats in a fluid of densityρf. The block is pushed down and released. Which quantity has nothing to do with the frequency of "simple harmonic motion" it will execute? (A)ρB；(B)ρf；(C)A；(D) All； (E) None.
8. Two sound waves differ in their intensity levels by 20 dB. What is the ratio of their displacement amplitudes? (A) 2； (B) 10； (C) 100； (D) 400； (E) None.
9. A cylindrical tank of height H is open at the top and has a diameter of D. It is filled with water up to a height of h. Which quantity is linearly proportional to the time it takes to empty the tank through a hole of radius R in its bottom? (A) H； (B) D； (C) h； (D) R； (E) None.

10. A traveling wave on a string of linear density μ can be described by the wave function y(x, t) = A sin (Bx+ Ct+ D) where A, B, C, D are all positive constants. Which statement is not correct?. (A) wavelength (λ) =2 π /C；(B) velocity of the wave (U) = CIB ；(C) tension (F) = μC2/B2, (D) All； (E) None.

11. A monatomic gas undergoes the set of thermodynamic processes shown in Fig. 2. There are n mol of gas. Which statement is correct?(A) TB = Tc； (B) The total work done on the gas during one cycle is (PA -PB) (VC - VB)； (C) The heat is transferred when the gas goes from B to C is (3/2) PB (VC - VB)； (D) AIl； (E) None.
12. A non-conducting sphere of radius R has a total charge Q spread uniformly throughout its volume. What is the potential energy U of the sphere?k = Coulomb-law constant) (A) kQ2/R； (B)kQ2/2R；(C) 3kQ2/2R； (D) 3kQ2/4R；(E) 3kQ2/5R.
13. When a ductile metal wire is stretched to N times its original length (without changing its density and resistivity), the resistance R will change by a factor of (A) 1/N2； (B) 1/N； (C) N； (D) N2； (E) None.
14. Which phenomenon can be analyzed by the mathematical tool of "phasor"? (A) ac circuits； (B) Interference of multiple slits； (C) Diffraction of a single slit； (D) All； (E) None.
15. A capacitor of capacitance Ci is charged to a potential difference V. The terminals of the charged capacitor are then connected to those of an uncharged C2 capacitor. Which statement is correct for this procedure?(A) The original charge of the system is C1V； (B) The final potential difference across each capacitor is C1 V/ (C1 + C2)； (C) The total electrical energy of the system decreases when the two capacitors are connected； (D) All； (E) None.
16. The potential difference across the terminals of a battery is V1when there is a current of I1 in the battery from the negative to the positive terminal. When the current is Iz in the reverse direction, the potential difference becomes V.. (Note that V1, V2, I1 and I2 are all defined as positive values)Which statement is not correct for this system? (A) V1 = V2； (B) The internal resistance of the battery is (V2 - V1)/( I1 + I2)； (C) The enf of the battery is ( I1V2 +  I2V1 )/(I1 + I2)； (D) All； (E) None.

17. Adc motor with its rotor and field coils connected in series has an internal resistance of R. When the motor is running at full load on a supply of V, the emf in the rotor is . Which statement is not correct for this system?(A) The current drawn by the motor from the supply is (V-ε )/R； (B) The power delivered to the motor is V(V-ε )ε/R； (C) The mechanical power developed by the motor is (V-ε) ε /R； (D) All； (E) None.

18. A slender metal rod of length L rotates with an angular speed of ω about an axis through one end and perpendicular to the rod. The plane of rotation of the rod is perpendicular to a uniform magnetic field with a magnitude of B. Which statement is not correct for this system? (A) The induced emf in the rod is ωBL2 ； (B) The potential difference between its ends is ωBL2/2 ； (C) The induced emf in the rod is equal to the potential difference between its ends； (D) All； (E) None.

19. Which is not an appropriate pair of analogy between mechanical and electrical quantities of the oscillating systems?(A)vI；(B)kC；(C)mL；(D) FV；(E) None. (k = spring constant)

20. An electromagnetic wave has an electric field given by E(y,t) = E0 k cos(ky -ωt). Which statement is not correct?(A) The wave is traveling in (+y) direction； (B) It is polarized along x-direction； (C) B(y,t) =(E0/c) i cos(k y - ωt)； (D) All； (E) None.
21. Which is necessary for two sources of waves to be "coherent"?(A) They are "in phase"； (B) They have the same amplitude； (C) They have the same frequency； (D) All；(E) None.
22. The image of a real object produced by a convex mirror is (A) virtual； (B) erect； (C) reduced； (D) All； (E) None.
23. Which quantity of the electron in a hydrogen atom is a constant multiplied by an integer in Bohr's model? (A) Linear momentum； (B) Angular momentum； (C) Binding energy； (D) All； (E) None.

24. An electron is accelerated by a voltage from rest until the wavelength of its matter wave is λ.What is the accelerating voltage V ?(A) h2/(2meλ2)；(B) h2(meλ2)； (C) h2/(2meλ)； (D) h(2meλ2)； (E) None. (h = Planck's constant)
25. Which behavior in the "photoelectric effect" can also be explained by the wave theory of light? (A) There is a "threshold frequency" for the incident light；(B) The "stopping potential" is not dependent on the intensity of light； (C) The "photocurrent" is proportionl to the intensity of light； (D) All. (E) None.

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