如图,Rt△ABC∽Rt△DEF,∠A=35°,则∠E的度数为( ).
A:35°
B:45°
C:55°
D:65°
如图甲是“测量小灯泡额定功率”的实验电路图,已知小灯泡的额定电压为3.8V.
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已知质量数为A的某阳离子Rn+,核外有x个电子,则核内中子数为( )
____+____=____
____-____=____