1/5单选题
难度：
1.
小明手头有电源一个（可调）、电压表一块、20Ω的定值电阻一个、导线若干、未知电阻Rx 一个 。若要测未知电阻Rx 的阻值，还必须的器材是（ ）
| A | 滑动变阻器一个 |
| B | 刻度尺一把 |
| C | 开关两个 |
| D | 小灯泡一个 |
- 提示1：
- PHA+5Y2V5LyP5rOV5rWL55S16Zi75b+F6aG76KaB5pyJ55S15Y6L6KGo44CB5a6a5YC855S16Zi75ZKM5Lik5Liq5byA5YWzPC9wPg==
正确答案：Qw==
PHA+5a6J6Zi75rOV5rWL55S16Zi75Lit5Yi75bqm5bC65ZKM5bCP54Gv5rOh5pi+54S25piv5rKh55So55qE77yMQuOAgUTplJnor6/jgILmu5Hliqjlj5jpmLvlmajlj6/ku6XmnInvvIzkvYbkuI3mmK/lv4XpobvnmoTjgILmraPnoa7nrZTmoYjvvJpDPC9wPg==
2/5单选题
难度：
2.
小兵同学用一块电压表和阻值已知的定值电阻R0测量未知电阻Rx的阻值。下列步骤中不合理的是（ ）
| A | 断开开关，连接好电路 |
| B | 只闭合开关S1时，电压表示数用U1表示 |
| C | 只闭合开关S2时，电压表示数用U2表示 |
| D | 同时闭合开关S1、S2，电压表示数为U1+ U2 |
- 提示1：
- PHA+6L+e5o6l5a6e6aqM55S16Lev5pe277yM5byA5YWz5b+F6aG75pat5byAPC9wPg==
- 提示2：
- PHA+5Y+q6Zet5ZCIUzxzdWI+MTwvc3ViPuaXtu+8jFI8c3ViPjA8L3N1Yj7jgIFSPHN1Yj54PC9zdWI+5Liy6IGU77yM55S15Y6L6KGo5rWLUjxzdWI+MDwvc3ViPuS4pOerr+eUteWOizwvcD4=
- 提示3：
- PHA+5Y+q6Zet5ZCIUzxzdWI+Mjwvc3ViPuaXtu+8jOeUteWOi+ihqOa1i+eUtea6kOeUteWOiywg5ZCM5pe26Zet5ZCIUzxzdWI+MTwvc3ViPuOAgVM8c3ViPjI8L3N1Yj7vvIxSPHN1Yj54PC9zdWI+6KKr55+t6Lev77yM55S15Y6L6KGo5LuN54S25rWL55S15rqQ55S15Y6LPC9wPg==
正确答案：RA==
PHA+5Y+q6Zet5ZCIUzxzdWI+MTwvc3ViPuaXtu+8jFI8c3ViPjA8L3N1Yj7jgIFSPHN1Yj54PC9zdWI+5Liy6IGU77yM55S15Y6L6KGo5rWLUjxzdWI+MDwvc3ViPuS4pOerr+eUteWOi+S4ulU8c3ViPjE8L3N1Yj4s5Y+q6Zet5ZCIUzxzdWI+Mjwvc3ViPuaXtu+8jOeUteWOi+ihqOa1i+eUtea6kOeUteWOi+S4ulU8c3ViPjI8L3N1Yj7vvJs8YnI+5ZCM5pe26Zet5ZCIUzxzdWI+MTwvc3ViPuOAgVM8c3ViPjI8L3N1Yj7vvIxSPHN1Yj54PC9zdWI+6KKr55+t6Lev77yM55S15Y6L6KGo5LuN54S25rWL55S15rqQ55S15Y6L77yM5Zug5q2k55S15Y6L6KGo56S65pWw5LuN54S25Li6PGk+VTwvaT48c3ViPjI8L3N1Yj7vvIzmiYDku6XpgIlEPHN1Yj7vvIw8L3N1Yj48L3A+
3/5单选题
难度：
3.
小敏同学用一块电压表和阻值已知的定值电阻R0测量未知电阻Rx的阻值。只闭合开关S1时，电压表示数用U1表示；只闭合开关S2时，电压表示数用U2表示；下列关于电阻Rx的表达式正确的是 （ ）
| A |
|
| B |
|
| C |
|
| D |
|
- 提示1：
- PHA+5Y+q6ZetPGltZyBzcmM9Imh0dHBzOi8vcDEucWluZ2d1by5jb20vRzEvTTAwLzJDLzAwL3JCQUNGRlBRME51UzUtWjhBQUFBcEc3OHhzczgzNy5wbmciIGRhdGEtY2tlLXNhdmVkLXNyYz0iaHR0cHM6Ly9wMS5xaW5nZ3VvLmNvbS9HMS9NMDAvMkMvMDAvckJBQ0ZGUFEwTnVTNS1aOEFBQUFwRzc4eHNzODM3LnBuZyIgaGVpZ2h0PSIyIiB3aWR0aD0iMiI+5ZCI5byA5YWzUzxzdWI+MTwvc3ViPiDvvIw8aT5SPC9pPjxzdWI+MCA8L3N1Yj7lkow8aT5SPC9pPjxzdWI+eCA8L3N1Yj7kuLLogZQ8c3ViPiA8L3N1Yj7vvIznlLXljovooajmtYs8aT5SPC9pPjxzdWI+MDwvc3ViPuS4pOerr+eUteWOizwvcD4=
- 提示2：
- PHA+5Y+q6Zet5ZCI5byA5YWzIFM8c3ViPjI8L3N1Yj7ml7YsPGk+IFI8L2k+PHN1Yj4wIDwvc3ViPuWSjDxpPlI8L2k+PHN1Yj54IDwvc3ViPuS7jeeEtuaYr+S4suiBlO+8jOeUteWOi+ihqOa1i+eUtea6kOeUteWOizwvcD4=
- 提示3：
- PHA+5qC55o2u5YiG5Y6L5Y6f55CGPGltZyBzcmM9Imh0dHBzOi8vcDIucWluZ2d1by5jb20vRzEvTTAwLzJDLzAwL3JCQUNGRlBRME51RG9KZklBQUFCLWhNLWRaTTEzOC5wbmciIGRhdGEtY2tlLXNhdmVkLXNyYz0iaHR0cHM6Ly9wMi5xaW5nZ3VvLmNvbS9HMS9NMDAvMkMvMDAvckJBQ0ZGUFEwTnVEb0pmSUFBQUItaE0tZFpNMTM4LnBuZyIgaGVpZ2h0PSI0MiIgd2lkdGg9IjYxIj48L3A+
正确答案：RA==
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
4/5单选题
难度：
4.
小梅想利用一块电压表和阻值已知的电阻R0测量电阻Rx的阻值。她选择了满足实验要求的器材，连接了实验电路，如图所示。当闭
合开关S1断开开关S2时,电压表的示数为U1；当闭合开关S1、 S2时,电压表的示数为为U2。下列Rx表达式正确的是（ ）
| A |
|
| B |
|
| C |
|
| D |
|
- 提示1：
- PHA+6ZetPGltZyBzcmM9Imh0dHBzOi8vcDIucWluZ2d1by5jb20vRzEvTTAwLzJDLzFBL3JCQUNGRlBRMDV1aThOTnJBQUFBcEEzZDhKSTY3NC5wbmciIGRhdGEtY2tlLXNhdmVkLXNyYz0iaHR0cHM6Ly9wMi5xaW5nZ3VvLmNvbS9HMS9NMDAvMkMvMUEvckJBQ0ZGUFEwNXVpOE5OckFBQUFwQTNkOEpJNjc0LnBuZyIgaGVpZ2h0PSIyIiB3aWR0aD0iMiI+5ZCI5byA5YWzUzxzdWI+MTwvc3ViPuaWreW8gOW8gOWFs1M8c3ViPjI8L3N1Yj7ml7bvvIw8aT5SPC9pPjxzdWI+MCA8L3N1Yj7lkow8aT5SPC9pPjxzdWI+eCA8L3N1Yj7kuLLogZQ8c3ViPiA8L3N1Yj7vvIznlLXljovooajmtYs8aT5SPC9pPjxzdWI+MDwvc3ViPuS4pOerr+eUteWOizwvcD4=
- 提示2：
- PHA+6Zet5ZCI5byA5YWzUzxzdWI+MTwvc3ViPuOAgSBTPHN1Yj4yPC9zdWI+5pe2LDxpPiBSPC9pPjxzdWI+eDwvc3ViPuiiq+efrei3r++8jOeUteWOi+ihqOa1i+eUtea6kOeUteWOizwvcD4=
- 提示3：
- PHA+5qC55o2u5YiG5Y6L5Y6f55CGPGltZyBzcmM9Imh0dHBzOi8vcDIucWluZ2d1by5jb20vRzEvTTAwLzJDLzFBL3JCQUNGRlBRMDV1QXRjX3VBQUFCLW5VME5mZzkxNS5wbmciIGRhdGEtY2tlLXNhdmVkLXNyYz0iaHR0cHM6Ly9wMi5xaW5nZ3VvLmNvbS9HMS9NMDAvMkMvMUEvckJBQ0ZGUFEwNXVBdGNfdUFBQUItblUwTmZnOTE1LnBuZyIgaGVpZ2h0PSI0MiIgd2lkdGg9IjYxIj48L3A+
正确答案：Qg==
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
5/5单选题
难度：
5.
小新同学想利用一块电压表和阻值已知的电阻R0测量电阻RX的阻值。她选择器材，并连接好实验电路， 其中电源电压恒定不变（但具体电压值未知）。开关S和S1都闭合时，电压表的示数为U1 ；只闭合开关S时，电压表的示数为U2 ；表示。下列关于电阻Rx的表达式正确的是 （ ）
| A |
|
| B |
|
| C |
|
| D |
|
- 提示1：
- PHA+5byA5YWzUzxzdWI+IDwvc3ViPuWSjFM8c3ViPjE8L3N1Yj7pg73pl63lkIjml7bvvIw8aT4gUjwvaT48c3ViPnggPC9zdWI+6KKr55+t6Lev77yM55S15Y6L6KGo55qE56S65pWwPGk+VTwvaT48c3ViPjE8L3N1Yj7kuLrnlLXmupDnlLXljos8L3A+
- 提示2：
- PHA+5Y+q6Zet5ZCI5byA5YWzIFPml7YsPGk+IFI8L2k+PHN1Yj4wIDwvc3ViPuWSjDxpPlI8L2k+PHN1Yj54IDwvc3ViPuS4suiBlO+8jOeUteWOi+ihqOa1izxpPlI8L2k+PHN1Yj4wPC9zdWI+5Lik56uv55S15Y6L5Li6PGltZyBzcmM9Imh0dHBzOi8vcDEucWluZ2d1by5jb20vRzEvTTAwLzY5LzI0L3JCQUNFMVBRems2VDVYaTZBQUFCVGl6b0otUTY2MC5wbmciIGRhdGEtY2tlLXNhdmVkLXNyYz0iaHR0cHM6Ly9wMS5xaW5nZ3VvLmNvbS9HMS9NMDAvNjkvMjQvckJBQ0UxUFF6azZUNVhpNkFBQUJUaXpvSi1RNjYwLnBuZyIgaGVpZ2h0PSIyMSIgd2lkdGg9IjE1Ij48L3A+
- 提示3：
- PHA+5qC55o2u5YiG5Y6L5Y6f55CGPGltZyBzcmM9Imh0dHBzOi8vcDEucWluZ2d1by5jb20vRzEvTTAwLzJCL0VCL3JCQUNGRlBRems2Q1VZeTZBQUFCOXgyZUhnQTI0MC5wbmciIGRhdGEtY2tlLXNhdmVkLXNyYz0iaHR0cHM6Ly9wMS5xaW5nZ3VvLmNvbS9HMS9NMDAvMkIvRUIvckJBQ0ZGUFF6azZDVVl5NkFBQUI5eDJlSGdBMjQwLnBuZyIgaGVpZ2h0PSI0MiIgd2lkdGg9IjYxIj48L3A+
正确答案：Qw==
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