矩形导线框abcd在磁场中以一定的角速度ω绕OO'轴旋转时可产生正弦交流电,在t=0时刻,线圈平面与匀强磁场垂直,如图所示,若规定电流沿逆时针方向为正,则下列四
A <img width="164" height="82" src="https://www.beizhujiaoyu.com/uploads/202208/20210727163433_1385.jpg" /> B <img width="165" height="82" src="https://www.beizhujiaoyu.com/uploads/202208/20210727163434_4309.jpg" /> C <img width="164" height="82" src="https://www.beizhujiaoyu.com/uploads/202208/20210727163435_2179.jpg" /> D <img width="164" height="83" src="https://www.beizhujiaoyu.com/uploads/202208/20210727163436_5089.jpg" />