题目

穿过闭合回路的磁通量Φ随时间t变化的图像分别如图甲、乙、丙、丁所示，下列关于回路中产生的感应电动势的论述，正确的是                                               （       ）甲                  乙                   丙                  丁（A）图甲中回路产生的感应电动势恒定不变（B）图乙中回路产生的感应电动势一直在变大（C）图丙中回路在0～t1时间内产生的感应电动势大于在t1～t2 Your donation_________ and the money will be used to help the students from poor families. A. is greatly appreciating              B. appreciates C. has appreciated                      D. is greatly appreciated