_ _ ^ _
1.若空间任意点电场B=Ar x k 其中r是该点的位置向量,A是个常数,则经过一个位于xy平面,
以原点为中心,半径为R的圆圈的净电流为?
2.若一平面电磁波电场振幅为100V/m,则其电厂振幅为?T
3.总质量为M的火箭,以30度仰角发射,初速V射出,达最高点时与发射原点的水平距离
为D,并于最高点分成2个等质量的部份,其中一部份自由落下,请问另一部份落地时,
与发射点的水平距离为?
4.Consider the RC circuit that has been
disconnected for a very long time before switching
on at the time t = 0.
(a) Find the voltage across the capacitor right after
switching on the switch S.
(b) Find the initial current I(0) that flows through the
resistor 4欧姆t = 0
(c) Find the current I(t) that flows through the
resistor 4欧姆 t > 0
(d) Find the current I1(t) that flows through the
resistor 8欧姆 t > 0
图在下
_____电阻(4欧姆)____/ S______________
| | |
| | |
| 电阻(8欧姆) 电容(0.5F)
电池(5V) | |
| | |
|___________________________|_________|
5.Consider a system of 1 mole of
oxygen gas at temperature 1000 oC. The oxygen
gas undergoes free expansion and triples its volume.
Find the entropy change in the free expansion.
以上 谢谢各位!
感激不尽