国立中山大学101学年度普通物理(二)期末考102-中山大学物理系.docVIP

國立中山大學101學年度普通物理(二)期末考 102.6.19 答題須知： 一、請由答題紙第六列開始作答，並標明題號。考試時間為19：00~21：30，20：00以後方可交卷。 二、請務必詳列相關公式及計算過程，記得寫上單位，並以M.K.S制表示。 (10%) A long coaxial cable with length l was modeled as a thin, cylindrical conducting shell of radius b concentric with a solid cylinder of radius a in Fig. 1. The conductors carry the same current I in opposite directions. Calculate the inductance L of this cable. (10%) In Fig. 2, the magnetic flux through the loop increases according to the relation (B = 6.0t2 ( 7.0t, where (B is in milliwebers and t is in seconds. (a) What is the magnitude of the emf induced in the loop when t = 2.0 s? (b) Is the direction of the current through R to the right or left? (15%) In Fig. 3, R = 14.0 Ω, C = 6.20μF, and L = 54.0 mH, and the ideal battery has emf ε = 34.0 V. The switch is kept at a for a long time and then thrown to position b. (a) Find the maximum charge that will appear on the capacitor. What are the (b) frequency and (c) current amplitude of the resulting oscillations? (1) (16%) Write down Maxwell’s Equations of electromagnetism on the assumption that no dielectric or magnetic materials are present and explain the characteristic of theses equations. (2) In Fig. 4, a parallel-plate capacitor has square plates of edge length L = 1.0 m. A current of 2.0 A charges the capacitor, producing a uniform electric field between the plates, with perpendicular to the plates. (3%) What is the displacement current id through the region between the plates? (3%) What is dE/dt in this region? (3%) What is the displacement current encircled by the square dashed path of edge length d = 0.50 m? (15%) In Fig. 5(a), unpolarized light is sent into a system of three polarizing sheets. The angles θ1, θ2, and θ3 of the polarizing directions are measured counterclockwise from the positive direction of the y axis. Angles θ1 and θ3 are fixed, but angle θ2 can be varied. Fig. 5(b) gives the intensity of t