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2003年高考物理(江苏卷)第13题: 要测量一块多用电表直流10 mA挡的内阻RA(约为40Ω),除此多用电表外,还有下列器材:直流电源一个(电动势E约为1.5 V,内阻可忽略不计),电阻一个(阻值R约为150Ω),电键一个,导线若干 要求:(1)写出实验步骤;(2)给出RA的表达式. [解答](1)实验步骤:①用多用电表的直流电压挡测量电源电动势E;②用多用电表的欧姆挡测电阻阻值R;③将多用电表置于直流10 mA挡,与电阻R及电键串联后接在电源两端,合上电键,记下多用电表读数I.
2003 College Entrance Examination Physics (Jiangsu Vol.) Item 13: To measure the internal resistance RA of a multi-meter DC 10 mA block (approximately 40Ω), in addition to this multimeter, the following equipment is also available: One for DC power (Equipotential E is approximately 1.5 V, the internal resistance is negligible), the resistance is one (resistance R is about 150 Ω), the electric key is one, the wire several requests: (1) writes the experimental procedure; (2) gives the expression of RA. [Answer] ( 1) Experimental procedure: 1 Measure the power EMF with the multi-meter’s DC voltage block; 2 Use the multimeter’s ohms to measure the resistance of the resistor R; 3 Place the multimeter in the DC 10 mA block, connect it in series with the resistor R and the key. At both ends of the power supply, close the key and write down the multimeter reading I.