在电源电压不变的情况下,为使正常工作的电热器在单位时间内产生的热量增加一倍,下列措施可行的是[ ]
在电源电压不变时,为了使电炉在相等的时间内发热多些,可采取的措施是 ( )
A.增大电热丝的电阻 B.减小电热丝的电阻
C.在电热丝上并联电阻 D.在电热丝上串联电阻
人气：307 ℃ 时间：2019-08-21 12:01:19
解答
C 并联电阻,电阻变小,由P=U平方/R 得 R小,功率变大,所以是CB为什么不对？电热丝是纯电阻电路，他是靠电流的热效应来发热，所以不能减小电阻
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