英语翻译which of the following practice can increase the electromagnet A.larger increase in currentB.nailsC.increase in coil

英语翻译which of the following practice can increase the electromagnet A.larger increase in currentB.nailsC.increase in coil
英语翻译
which of the following practice can increase the electromagnet
A.larger increase in current
B.nails
C.increase in coil

英语翻译which of the following practice can increase the electromagnet A.larger increase in currentB.nailsC.increase in coil
下面哪种方法可以增加电磁
1）增加电流
2）钉钉子
3）增加线圈