一个未知电阻Rx，阻值大约为10kΩ-20kΩ．为了较为准确的测定其电阻值，实验室中有如下器材：电压表V1
\u4e00\u4e2a\u672a\u77e5\u7535\u963bR x \uff0c\u963b\u503c\u5927\u7ea6\u4e3a10k\u03a9-20k\u03a9\uff0c\u4e3a\u4e86\u8f83\u4e3a\u51c6\u786e\u5730\u6d4b\u5b9a\u5176\u7535\u963b\u503c\uff0c\u5b9e\u9a8c\u5ba4\u4e2d\u6709\u5982\u4e0b\u5668\u6750\uff1a\u7535\u538b\u8868V 1\uff081\uff09\u6839\u636e\u5f85\u6d4b\u7535\u963b\u7684\u5927\u5c0f\u548c\u7535\u6e90\u7684\u7535\u52a8\u52bf\u5927\u5c0f\uff0c\u4f30\u6d4b\u7535\u8def\u4e2d\u7684\u6700\u5927\u7535\u6d41\u4e0d\u4f1a\u8d85\u8fc730mA\uff0c\u6545\u7535\u6d41\u8868\u9009\u62e9A 1 \uff0c\u7535\u538b\u8868\u9009\u62e9V 1 \uff0e\u6545\u7b54\u6848\u4e3a\uff1aV 1 \uff0cA 1 \uff0e\uff082\uff09\u7531\u4e8e\u6240\u7ed9\u6ed1\u52a8\u53d8\u963b\u5668\u592a\u5c0f\uff0c\u5f85\u6d4b\u7535\u963b\u5f88\u5927\uff0c\u56e0\u6b64\u8be5\u5b9e\u9a8c\u91c7\u7528\u6ed1\u52a8\u53d8\u963b\u5668\u7684\u5206\u538b\u63a5\u6cd5\u548c\u7535\u6d41\u8868\u7684\u5185\u63a5\u6cd5\uff0c\u5177\u4f53\u7535\u8def\u56fe\u5982\u4e0b\u6240\u793a\uff1a
\u89e3\uff1ba\u3001\u56e0\u7535\u6e90\u7535\u52a8\u52bf\u4e3a3V\uff0c\u6240\u4ee5\u7535\u538b\u8868\u91cf\u7a0b\u5e94\u90093V\uff1b\u6839\u636e\u6b27\u59c6\u5b9a\u5f8b\u53ef\u6c42\u51fa\u901a\u8fc7\u5f85\u6d4b\u7535\u963b\u7684\u7535\u6d41 I= U R = 3 10 mA- 3 20 mA \uff0c\u6240\u4ee5\u7535\u6d41\u8868\u5e94\u9009A 1 \uff0eb\u3001\u7531\u4e8e\u5f85\u6d4b\u7535\u963b\u7684\u7535\u963b\u503c\u6bd4\u8f83\u5927\uff0c\uff08\u6bd4V 1 \u7684\u5185\u963b\u8fd8\u5927\uff09\uff0c\u6240\u4ee5\u7535\u6d41\u8868\u5e94\u7528\u5185\u63a5\u6cd5\uff1b\u7531\u4e8e\u6ed1\u52a8\u53d8\u963b\u5668\u6700\u5927\u963b\u503c\u8fdc\u5c0f\u4e8e\u5f85\u6d4b\u7535\u963b\uff0c\u53d8\u963b\u5668\u5e94\u7528\u5206\u538b\u5f0f\u63a5\u6cd5\uff0c\u7535\u8def\u56fe\u5982\u56fe\u6240\u793a\uff1a c\u3001\u5b9e\u7269\u56fe\u8fde\u7ebf\u5982\u56fe\u6240\u793a\uff1b \u6545\u7b54\u6848\u4e3a\uff1aa V 1 \uff0cA 1 \uff1bb \u5982\u56fe\uff1b c \u5982\u56fe
解答：解；a、因电源电动势为3V，所以电压表量程应选3V；根据欧姆定律可求出通过待测电阻的电流I＝
| U |
| R |
| 3 |
| 10 |
| 3 |
| 20 |
b、由于待测电阻的电阻值比较大，（比V1的内阻还大），所以电流表应用内接法；
由于滑动变阻器最大阻值远小于待测电阻，变阻器应用分压式接法，电路图如图所示：
c、实物图连线如图所示；
故答案为：a V1，A1；b 如图； c 如图
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