题目内容
如图所示,单匝线圈在匀强磁场中绕
轴从图示位置开匀速转动.已知从图示位置转过
时,线圈中电动势大小为10V,求:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241403452664874.jpg)
(1)交变电动势的峰值,
(2)交变电动势的有效值;
(3)设线圈电阻为R=1Ω,角速度ω=100rad/s,求线圈由图示位置转过
过程中通过导线截面的电荷量
(4)写出交变电流电动势瞬时值的表达式
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824140345063364.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824140345172420.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241403452664874.jpg)
(1)交变电动势的峰值,
(2)交变电动势的有效值;
(3)设线圈电阻为R=1Ω,角速度ω=100rad/s,求线圈由图示位置转过
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824140345313421.png)
(4)写出交变电流电动势瞬时值的表达式
(1) 8.0 V(2) 2.88 W(3) 4.0×10-3 C.
(1)由图象知,线圈中产生的交变电流的周期
T=3.14×10-2 s,所以Em=nBmSω=
=8.0 V. (1分)
(2)电流的最大值Im=
=0.80 A,(1分)
有效值I=
=
A,(1分)
小灯泡消耗的电功率P=I2R=2.88 W. (1分)
(3)在0~
时间内,电动势的平均值
=
,平均电流![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241403457651156.png)
流过灯泡的电荷量Q=
Δt=
=4.0×10-3 C. (1分)
本题考查交流电的产生过程。根据图像可得交流电的周期,然后可求出交流电压的最大值,以及有效值,根据欧姆定律可得交流电流的最大值,以及交流电流有效值,求通过的电量时利用法拉第电磁感应定律求平均电动势,然后求出平均电流,即可求出电量,
T=3.14×10-2 s,所以Em=nBmSω=
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824140345406712.png)
(2)电流的最大值Im=
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824140345453616.png)
有效值I=
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824140345547518.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824140345594480.png)
小灯泡消耗的电功率P=I2R=2.88 W. (1分)
(3)在0~
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824140345640389.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824140345687320.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824140345718682.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241403457651156.png)
流过灯泡的电荷量Q=
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824140345828268.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824140345906724.png)
本题考查交流电的产生过程。根据图像可得交流电的周期,然后可求出交流电压的最大值,以及有效值,根据欧姆定律可得交流电流的最大值,以及交流电流有效值,求通过的电量时利用法拉第电磁感应定律求平均电动势,然后求出平均电流,即可求出电量,
![](http://thumb2018.1010pic.com/images/loading.gif)
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