如图所示,1、2两个闭合圆形线圈用同样的导线制成,匝数n1=2n2,半径R1=2R2,图示区域内有均匀磁场,其磁感应强度随时间均匀减小.则下列判断正确的是( )
A:1、2线圈中产生的感应电动势之比E1:E2=4:1
B:1、2线圈中产生的感应电动势之比E1:E2=8:1
C:1、2线圈中感应电流之比I1:I2=4:1
D:1、2线圈中感应电流之比I1:I2=2:1
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Sally is an English girl. She is my English teacher, Mrs Brown's daughter. She is only five years old. She doesn't go to school. She likes playing ping-pong. Her favorite ping-pong player is Zhang Yining. Sally is in the ping-pong club. She goes to the ping-pong club every day. She plays ping-pong for two hours there. Sally has a sister. Her name is Maria. She is in our class. She likes singing. (A) She wants to join the music club, she sings every morning. (B)Her favorite singing star is Song Zuying. Maria says she wants to be a singing star like Song Zuying.
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