efk5ef5qv6a3d
幼苗
共回答了16个问题采纳率:93.8% 举报
(1)由于加热电阻只能单独工作,加热电阻消耗的热功率最大只可能是
![](https://img.yulucn.com/upload/a/85/a855904b2e36a33d64a08e0d36a4bc16_thumb.jpg)
或
![](https://img.yulucn.com/upload/5/89/58958cde0f9ace6589dec7890f7eba2e_thumb.jpg)
单独接在电路中时。
设电源两端电压为U,当
![](https://img.yulucn.com/upload/4/54/454aab4144d24fcac6c8c493558c6412_thumb.jpg)
单独工作时,由题意可知加热电阻
![](https://img.yulucn.com/upload/b/fc/bfc2aa9b3718d9a3fe2d1a4bb42d2378_thumb.jpg)
消耗的热功率为90W。
当电路中只有
![](https://img.yulucn.com/upload/0/7f/07fd7fd51d702569ca7730ce8034e906_thumb.jpg)
单独工作时,加热电阻消耗的功率为
![](https://img.yulucn.com/upload/0/95/095b8bf917487fd9d4b80a9d2ddcc78f_thumb.jpg)
,由于电源电压不变,所以
![](https://img.yulucn.com/upload/b/fa/bfa8773b3b68c9843beae8f2ff4290b9_thumb.jpg)
加热器的加热电阻工作的最大热功率是
![](https://img.yulucn.com/upload/5/b0/5b056d58a1642c967cf6c17e9403e746_thumb.jpg)
单独工作时。
![](https://img.yulucn.com/upload/f/dc/fdcd09edf8a74bdb872a38257fa8bfda_thumb.jpg)
,此时需闭合
![](https://img.yulucn.com/upload/6/63/663f58c59793616b85d5ac8c84d3fded_thumb.jpg)
,断开
![](https://img.yulucn.com/upload/5/e9/5e946eb44b3413f2a2dfa385d8af1a17_thumb.jpg)
。
(2)电路中
![](https://img.yulucn.com/upload/a/f6/af639a74e8f39d1a80775903e0b70511_thumb.jpg)
、
![](https://img.yulucn.com/upload/a/4a/a4a4806c95869adb9996e4ca026ac5c7_thumb.jpg)
分别单独工作时消耗的热功率都比
![](https://img.yulucn.com/upload/b/81/b81827baa7ed9fd507741c950b95728a_thumb.jpg)
、
![](https://img.yulucn.com/upload/e/e8/ee833d85b89af02dd769b99b273e0eba_thumb.jpg)
分别与
![](https://img.yulucn.com/upload/8/35/835857e007fa28a6434a34744a8fac4a_thumb.jpg)
串联消耗的热功率大,由于
![](https://img.yulucn.com/upload/7/ba/7baa310bc9b855ea0bbbc6e72d67230d_thumb.jpg)
、
![](https://img.yulucn.com/upload/f/7e/f7e7deafdce263e1a21461c5ea7709c9_thumb.jpg)
不能同时工作,电热器的加热电阻消耗的功率最小的时候可能是
![](https://img.yulucn.com/upload/d/cb/dcb1a57c9cde5688db5c6da50106c52c_thumb.jpg)
与
![](https://img.yulucn.com/upload/6/2f/62f9756ebd3248b27c8d45c71404c3e0_thumb.jpg)
串联时
![](https://img.yulucn.com/upload/6/84/684586ceabfec64fa8661b557f7e0699_thumb.jpg)
消耗的热功率最小或
![](https://img.yulucn.com/upload/4/87/487b050389624ce9a725ae1e504c64a3_thumb.jpg)
与
![](https://img.yulucn.com/upload/5/da/5dae8a89e00f2cdb6fdcb385bf9fdc66_thumb.jpg)
串联时
![](https://img.yulucn.com/upload/4/df/4df44a60d1d0f2d06037041ece37799f_thumb.jpg)
消耗的热功率最小。当只闭合
![](https://img.yulucn.com/upload/2/90/2903f22ede750c08869f41d81bd942af_thumb.jpg)
时,
![](https://img.yulucn.com/upload/7/d8/7d8ca1a9df553e0b0181511c88263020_thumb.jpg)
与
![](https://img.yulucn.com/upload/a/25/a254bfeb06fa20c7027170d5a0e9f472_thumb.jpg)
串联,设
![](https://img.yulucn.com/upload/f/ce/fce425e69f6a7173ab5af6a721168b05_thumb.jpg)
与
![](https://img.yulucn.com/upload/5/29/529c317dea78b5a6f7625e7b0ae0f133_thumb.jpg)
串联时,电路消耗的总功率和
![](https://img.yulucn.com/upload/1/cc/1ccdfdb0857458d13e8901bcce9fe63e_thumb.jpg)
消耗的功率分别为
![](https://img.yulucn.com/upload/4/c1/4c1d9d4659bae7f990d8ff9b06a4099b_thumb.jpg)
和
![](https://img.yulucn.com/upload/e/21/e21b321a1c1db72bb787cfc2bd7b16bd_thumb.jpg)
;
根据串联电路特点
![](https://img.yulucn.com/upload/4/e6/4e6756555aa8c3d64f5e247e4029642c_thumb.jpg)
,则
1年前
7