91年 - 91 淡江大學轉學考電磁學#56129

科目：研究所、轉學考(插大)◆電磁學 | 年份：91年 | 選擇題數：0 | 申論題數：14

試卷資訊

所屬科目：研究所、轉學考(插大)◆電磁學

選擇題 (0)

申論題 (14)

(a) Find the electric field a distance z above one end of the line as shown is Fig. 1. (10%)

(b) What field would you expect for the case z » L. Why? (5%)

(a) Find the surface charge density cr at Ry at a, and at b. (6%)

(b) Find the potential at the center, using infinity as the reference point. (10%)

(c) Now the outer surface is touched to a grounding wire. How do you answers to (a) and (b) change? (9%)

(a) What is the force on a point charge Q at (a, 0, 0) (Cartesian coordinates)? (6%)

(b) What is the force on Q at (0, 0, a)? (6%)

(c) How much work does it take to move Q from (a, 0，0) to (0，0, a)? (6%)

(a) Find the magnetic field a distance z above the center of the loop. (10%)

(b) Find the magnetic moment of the loop. (5%)

(a) Find the magnetic Field of the solenoid. (5%)

(b) Find the self-inductance per unit length of the solenoid. (5%)

(c) Find the energy stored in a section of length 1 of the solenoid. (5%)

6. At the interface between one linear magnetic material and another magnetic field lines bend (see Fig. 3). Show that tanθ₂ / tanθ₁ = μ₂/μ₁ assuming there is no free current at the boundary. (12%)