初三第二轮联考物理温习卷(国外英文资料).docVIP

初三第二轮联考物理复习卷 Second round physics review volume (circuit topic 1) 1, choice (3 points, 30 points) The length of the two copper wires is the same, the cross-sectional area of a is smaller than b, and now they are connected in the circuit. A and B are both voltages at both ends, so through its current is also large B and A wire resistance is large, so the current is small through its current C, a and b are of the same current, the voltage at each end is the same, the resistance of the b wire is small, and the voltage on both ends is small As shown in the circuit shown in figure 1, the power supply voltage is constant, and the circuit is working properly after closing the switch. After a while, the indicator of the ammeter is larger and the ratio of the voltmeter to the indicator of the ammeter is constant, and the following judgment is correct () A, resistance R breaks, lights L dimmed B, resistance R short circuit, light L is bright C, light L circuit, the number of the voltmeter decreases D, the lamp L short circuit, the indicator of the voltmeter is larger Figure 1 3, party a and b have two fixed value resistance, a marked 10 Ω 1 a, b marked Ω 2 a 5 . If they are concatenated in the circuit, the voltage at the ends of the circuit is the maximum (). A, 15, V, B, 30V, C, 20, D, 5V 4, as shown in figure 2 circuit, closed circuit work normally after switch, after a while, a meter readings and a second electric meter readings of the smaller, the judgment of the following is correct () A, the resistance R must be broken, the resistance R must be short circuit C, the brightness of the light L may be constant D, the lamp L may be bright Figure 2 As shown in the circuit shown in figure 3, the small light bulb is fully illuminated and the meter is in good condition after the closed switch. If the voltmeter is swapped with the current meter, then the situation is (). A, the number of the voltmeter is the same, the light bulb L1, L2 is not bright, the number of the voltmeter