在“用电流表和电压表测电阻”的实验中,所用的电源电压为6V,待测电阻约为15Ω.(1)甲同学连接的部分
\u5728\u201c\u7528\u7535\u6d41\u8868\u548c\u7535\u538b\u8868\u6d4b\u7535\u963b\u201d\u7684\u5b9e\u9a8c\u4e2d\uff0c\u6240\u7528\u7684\u7535\u6e90\u7535\u538b\u4e3a6V\uff0c\u5f85\u6d4b\u7535\u963b\u7ea6\u4e3a15\u03a9\uff0e\uff081\uff09\u7532\u540c\u5b66\u8fde\u63a5\u7684\u90e8\u5206\uff081\uff09\u7535\u6e90\u7535\u538b\u4e3a6V\uff0c\u7535\u538b\u8868\u9009\u62e90\uff5e15V\u91cf\u7a0b\uff0c\u7535\u538b\u8868\u4e0e\u5f85\u6d4b\u7535\u963b\u5e76\u8054\uff0e\u7535\u8def\u6700\u5927\u7535\u6d41\u4e3a\uff1aI=UR=6V15\u03a9=0.4A\uff1c0.6A\uff0c\u6240\u4ee5\u7535\u6d41\u8868\u9009\u62e90\uff5e0.6A\u91cf\u7a0b\uff0c\u7535\u6d41\u8868\u4e0e\u5f85\u6d4b\u7535\u963b\u4e32\u8054\uff0e\u7535\u6d41\u4ece\u7535\u538b\u8868\u548c\u7535\u6d41\u8868\u7684\u6b63\u63a5\u7ebf\u67f1\u8fde\u5165\uff0c\u4ece\u8d1f\u63a5\u7ebf\u67f1\u6d41\u51fa\uff0e\u6ed1\u52a8\u53d8\u963b\u5668\u5df2\u7ecf\u9009\u5b9a\u4e86\u4e0b\u9762\u63a5\u7ebf\u67f1\uff0c\u4efb\u610f\u9009\u62e9\u4e0a\u9762\u4e00\u4e2a\u63a5\u7ebf\u67f1\u4e32\u8054\u5728\u7535\u8def\u4e2d\uff0c\u5982\u56fe\uff1a\uff082\uff09\u4f0f\u5b89\u6cd5\u6d4b\u7535\u963b\u7684\u539f\u7406\u662f\u6b27\u59c6\u5b9a\u5f8b\uff0c\u5373I=UR\uff1b\uff083\uff09\u7535\u6d41\u8868\u9009\u62e90\uff5e0.6A\u91cf\u7a0b\uff0c\u6bcf\u4e00\u4e2a\u5927\u683c\u4ee3\u88680.2A\uff0c\u6bcf\u4e00\u4e2a\u5c0f\u683c\u4ee3\u88680.02A\uff0c\u7535\u6d41\u4e3a0.24A\uff0cR=UI=3V0.24A=12.5\u03a9\uff0e\uff084\uff09\u77e5\u9053\u6b64\u65f6\u7684\u7535\u538b\u662f3V\uff0c\u7535\u6d41\u662f0.24A\uff0c\u6545\u6b64\u65f6\u7684\u529f\u7387\u662f\uff1aP=UI=3V\u00d70.24A=0.72W\uff1b\u6545\u7b54\u6848\u4e3a\uff1a\uff081\uff09\u89c1\u4e0a\u56fe\uff1b\uff082\uff09I=UR\uff1b\uff083\uff090.24\uff1b12.5\uff1b\uff084\uff090.72\uff1b
1.\u7528\u7535\u538b\u8868\u6bd4\u8f83\uff1a\u7535\u6e90 \u5f00\u5173 \u548c\u7535\u963b\u4e32\u8054\u8fde\u63a5\u597d\uff0c\u7528\u7535\u538b\u8868\u5206\u522b\u6d4b\u4e24\u53ea\u7535\u963b\u4e24\u7aef\u7684\u7535\u538b\uff0c\u7535\u538b\u6570\u503c\u5927\u7684\u7535\u963b\u5c31\u5927\uff0c\u56e0\u4e3a
U=IR\uff0c\u4e32\u8054I\u4e00\u6837\u3002
2.\u7528\u7535\u6d41\u8868\u6bd4\u8f83\uff1a\u7535\u6e90 \u5f00\u5173 \u548c\u7535\u963b\u5e76\u8054\u8fde\u63a5\u597d\uff0c\u7528\u7535\u6d41\u8868\u5206\u522b\u6d4b\u91cf\u4e24\u53ea\u7535\u963b\u7684\u7535\u6d41\uff0c\u7535\u6d41\u6570\u503c\u5c0f\u7684\u7535\u963b\u5c31\u5927\uff0c\u56e0\u4e3a
R=U/I\uff0c\u5e76\u8054U\u662f\u4e00\u6837\u3002
电路最大电流为:I=
U |
R |
6V |
15Ω |
电流从电压表和电流表的正接线柱连入,从负接线柱流出.
滑动变阻器已经选定了下面接线柱,任意选择上面一个接线柱串联在电路中.如图.
(2)为了减小误差,需要完成多次实验--实验次数.
需要测电压--电压.
需要测电流--电流.
计算每一次的电阻--电阻.
计算电阻平均值--电阻平均值.
注意:物理量的后面标注单位,如下表:
实验次数 | U/V | I/A | R/Ω |
|