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Classification training Ohm's law
Proposition point classification training
Proposition point 2 Ohm's law dynamic circuit correlation calculation
Ι. Text expression class
10. (Harbin) resistors R1 and R2 are connected in series, the supply voltage is 10 V, the voltage across R1 is 8 V, and R1 is 10 Ω, then the current in R1 is equal to ________A, and R2 is equal to ________Ω____
11. (Tianjin) When the voltage across a conductor is 3 V, the current through it is 0.2 A, and the resistance of the conductor is __________Ω____Ω__
II. Simple circuit class
12. (Guangdong Volume) As shown in the figure, the resistance of bulb L1 and L2 is 10 Ω and 20 Ω, the closed switch S, the current through L1 and L2 is I1 and I2, and the voltages at both ends are U1 and U2, respectively, then ( )
A. I1∶I2＝1∶1，U1∶U2＝2∶1
B. I1∶I2＝1∶2，U1∶U2＝1∶1
C. I1∶I2＝1∶1，U1∶U2＝1∶2
D. I1∶I2=1∶2,U1∶U2=1∶2
13. (Meishan) As shown in the figure, the supply voltage remains unchanged. After closing the switch S, both lights can work normally. The ratio of the resistance of lamp L1 and L2 is R1:R2=1:2, and the ratio of the indication of the A and B meters at this time is ( )
A. 2∶1 B. 1∶2 C. 3∶2 D. 2∶3
III. Dynamic circuit class
15. (Fujian) As shown in the circuit, the supply voltage is constant, R1=12 Ω, R2=6 Ω, R3 is the fixed value resistor. Closed switch S1, sparrow and double throw switch S2 with an indication of 0.6 A for the ammeter when connected to a, and the indication of the ammeter when b is connected may be ( )
A. 0.3 A B. 0.6 A C. 0.9 A D. 1.2 A
16. (Guang'an) As shown in the circuit shown in the figure, the supply voltage is constant 4.5 V, the amperometer has a range of 0~0.6 A, the voltmeter has a range of 0~3 V, the fixed-value resistor resistance is 5 Ω, and the maximum resistance of the sliding varistor R is 50 Ω.
A. If slide P is shifted to the left, the ammeter's indication becomes smaller
B. The ratio of the voltmeter to the ammeter is unchanged
C. The allowable adjustment range of the sliding varistor is 2.5 Ω to 50 Ω
D. The range of the ammeter is 0.3 A to 0.6 A
17. (Hengyang) As shown in the figure, R is the fixed value resistor, R′ is the sliding varistor, the closed switch S, the sliding slide of the sliding varistor is gradually slid from the a-end to the b-end, and the V1 representation number changes from 2 V to 6 V, while the V2 representation changes from 4 V to 0, the current representation changes from 0.2 A to ________A, and R=________Ω__
18. (Xiangyang) As shown in the figure, the power supply voltage remains unchanged, the resistance R1 = R2 = R3 = 10 Ω. If only R2 and R3 are connected to the circuit in parallel, the switch should be closed ____________ at this time, and the indication of the ammeter is I1; to make R1 and R2 in series, the switches S1 and S2 should be disconnected, and the indication of the ammeter at this time is I2, then I1:I2=________
Ⅳ . U-I image class
19. (Huai'an) as shown in Figure (a) is the I-U image of resistors A and B; (b), (c) are some of their circuit connection schematics, the following statement is wrong ( )
A. When the voltage across resistor B is 2.5 V, its resistance is equal to that of A
B. In Figure (b), when the voltage U is 3 V, the resistance of B is 5 Ω
C. In Figure (c), when the voltage U is 2 V, the total trunk current is 0.6 A
D. In Figure (c), in the process of increasing the voltage U from 0 to 2.5 V, the difference between the currents through the resistors A and B first becomes larger and then smaller
20. (Anhui) The I-U image of resistors A and B is shown. If A and B are connected to both ends of a power supply in series, the ratio of voltage UA and UB at both ends is ________________V____
Refer to the answer
10. 0.8 2.5
11. 15 15
12. C
13. D
14. 1.5 0.3 12 10
15. C
16. D
17. 0.6 10
18. S1、S2 4∶1
19. B
20. 1∶2 2