题目内容
在LC回路中产生电磁振荡的过程中( ).
A.从电容器放电开始计时,当t=kπ![]() |
B.当电容器中电场强度增大时,线圈中的自感电动势与振荡电流方向相反 |
C.向电容器充电是磁场能转化成电场能的过程 |
D.电容器在相邻的充、放电时间内,电流方向一定相同 |
C
当t=kπ
(k=0,1,2……)时,由图可知振荡电路电流为零,A错误;当电场强度增大时,在
~
、
T~T时间段内,振荡电流减小,线圈中自感
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250037024711381.png)
电动势与振荡电流方向相同,B错;电容器充电时,电场能增大,磁场能减小,磁场能转化为电场能,C正确;相邻的充、放电时刻,在0~
、
~
、
~
T和
T~T等时间内,由图像对照,可知在
~
内,电容器充电,i>0,在
~
T内,电容器放电,i<0,D错误.
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003702362441.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003702393389.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003702424406.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003702455385.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250037024711381.png)
电动势与振荡电流方向相同,B错;电容器充电时,电场能增大,磁场能减小,磁场能转化为电场能,C正确;相邻的充、放电时刻,在0~
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003702393389.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003702393389.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003702424406.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003702424406.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003702455385.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003702455385.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003702393389.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003702424406.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003702424406.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003702455385.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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