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As the circuit shown in the figure, the power supply voltage is 12V, the resistance value of R1 is 10 Ω, the number of a meter and A1 is 1a and 0.4A respectively, then what is the resistance value of R2?
It can be seen from the circuit diagram that R1 and R2 are connected in series with sliding rheostat after parallel connection, ammeter a measures the current of main circuit, ammeter A1 measures the current of R1 branch; ∵ the current of main circuit in parallel circuit is equal to the sum of the currents of each branch, ∵ the current through R2 branch: I2 = i-i1 = 1a-0.4a = 0.6A, ∵ the voltage at both ends of each branch in parallel circuit is equal, ∵ according to Ohm's law, u = i1r1 = i2r2, that is 0.4A × 10 Ω = 0.4A 6A × R2, R2 ≈ 6.7 Ω. Answer: the resistance of R2 is 6.7 Ω
The reading of ammeter A1 is 0.5A, and that of ammeter A2 is 1.25A. If the resistance of R2 is 8 Ω, what is the resistance of R1
Parallel, so the voltage is equal
That is, the current and resistance are equal
So R1 = 20 Ω
In the circuit as shown in the figure, the resistance R1 = 12 ohm, R2 = R3 = R4 = 6 ohm. When the key K is open, the indication of the voltmeter is 12V, and the electric power consumed by the whole circuit is 13W. Calculate: (1) the electromotive force E and internal resistance r of the power supply. (2) after the key K is closed, what are the indication of the voltmeter and the ammeter? (the internal resistance of the ammeter is negligible, and the internal resistance of the voltmeter is very large)
(1) When the key s is disconnected, the total resistance of the external circuit is r outer = R4 + R1 (R2 + R3) R1 + R2 + R3 = 6 Ω + 6 Ω = 12 Ω, the total current is I = u outer r outer = 1212a = 1a. The electric power consumed by the whole circuit is p = EI, then the electromotive force of the power supply is e = pi = 13V. The internal resistance of the power supply is r = e − UI = 13 − 121 Ω = 1 Ω (2)
In the circuit shown in the figure, R1 = R2, when switch S is off, the indication of ammeter is 1a, when switch S is closed, the indication of ammeter will ()
A unchanged, B increased to 2a, C decreased to 0.5A, D increased to 4a
The picture shows that R1 and R2 are connected in parallel, and the ammeter is on the branch where R1 is located
A parallel circuit does not affect each other
RELATED INFORMATIONS
- 1. In the circuit shown in the figure, the voltage U remains unchanged, the resistance R1 = R2, when the switch S is open, the indication of the ammeter is I1; when the switch S is closed, the indication of the ammeter is I2, then I1: I2=______ ．
- 2. A series circuit ammeter calculates the current representation between two resistors
- 3. If two resistors R1 and R2 are connected to a 3V power supply, calculate the indication of the ammeter, and calculate the electric energy consumed when the 30s resistance is 3V
- 4. As shown in the figure, R1 = 6 Ω, the reading of ammeter A1 is 0.5A, and the degree of ammeter A2 is 0.3A? (2) What is the resistance of R2?
- 5. R is the resistance box, V is the ideal voltmeter, when the resistance box is R1 = 2 ohm, the voltmeter reading is U1 = 4V, when the number of resistance boxes is R2 = 5 ohm, the number of voltmeters is U2 R is the resistance box, V is the ideal voltmeter. When the resistance box is R1 = 2 ohm, the reading of the voltmeter is U1 = 4V. When the number of resistance boxes is R2 = 5 ohm, the number of voltmeters is U2 = 5V
- 6. As shown in the figure, when the power supply voltage remains unchanged and the switch S is closed, when the slide P of the sliding rheostat moves from left to right, the change of the three meters is () A. V1 increases, V2 decreases, a increases, B. V1 decreases, V2 increases, a decreases, C. V1 remains unchanged, V2 increases, a remains unchanged, D. V1 remains unchanged, V2 decreases, a remains unchanged
- 7. In the circuit as shown in the figure, the power supply voltage does not change. When s is closed and the slide P of the sliding rheostat moves from left to right, the change of the indication of the three meters is () A. A bigger, V1 unchanged, V2 bigger B. a bigger, V1 smaller, V2 unchanged C. A unchanged, V1 smaller, V2 bigger D. a smaller, V1 bigger, V2 bigger
- 8. When the switch is closed for the experiment, it is found that the voltmeter and ammeter show the number no matter how the slide rheostat is moved. What is the reason In the experiment of measuring constant resistance or measuring electric power of small bulb
- 9. For the existing power supply with unknown voltage [voltage unchanged], one ammeter, one voltmeter, one sliding rheostat [known maximum resistance is R0] and one resistance Rx to be measured, There are two switches and several wires. Please draw two different schemes of measuring RX resistance according to the requirements, and write down the experimental steps and the process and expression of calculating Rx
- 10. Use ammeter and voltmeter, measure the method of small bulb resistance to call voltammetry, what is the principle?
- 11. The power supply voltage is constant, R1 = 6ohm, R2 = 12ohm, sliding rheostat R3 = maximum resistance value 0, ammeter range is 0 ~ 0.6A, voltmeter range is 0 ~ 3V, open S1, close S2, the heat generated by current through R1 within 10 seconds is 60 joules, power supply voltage is u =? Sliding rheostat R3 = maximum resistance 20 ohm
- 12. As shown in the figure, in the circuit, the power supply voltage is constant, R1 = 6 Ω, R2 = 4 Ω. When S1 and S2 are closed, the indication of ammeter A1 is 1a, and the indication of ammeter A is 2.5A. Calculate: (1) the resistance value of resistance R3 and the indication of voltmeter. (2) when S1 and S2 are both open, the indication of ammeter A1, a and voltmeter v
- 13. As shown in the figure on the right, R1 = 30 ohm, R2 = 10 ohm. After closing the switch, the indication of ammeter A is 2a to calculate the power supply voltage!
- 14. For the circuit shown in the figure, the power supply voltage remains unchanged, R2 = 60 Ω. When the switch S is off, the indication of the ammeter is 0.5A; when the switch is closed, the indication of the ammeter is 0.6A. Calculate the resistance of R1
- 15. How to judge which electrical appliance is measured by Voltmeter and ammeter As the title I'm sorry. For example, if two switches are closed, which appliance is short circuited, and if two switches are open?
- 16. What is the effect of changing the 100 ohm resistance in series with the ammeter to 200 ohm in the circuit diagram of superposition theorem on the measurement result
- 17. There are the following equipment on the experimental table: a power supply, an ammeter and a voltmeter, a switch, a sliding rheostat, two resistance boxes, fixed resistance and wires with known resistance values. It is required to select appropriate equipment from the experimental table and design an experiment to prove: "when the voltage at both ends of the resistance remains unchanged, the electric power consumed by the resistance is the same as that consumed by the resistance The resistance of the resistance is inversely proportional. Please draw the experimental circuit diagram, write the experimental steps, and design the data recording form
- 18. Give you a resistance, voltmeter, switch, power supply and wire with known resistance value. Please design an experiment to measure the resistance value of unknown resistance Rx. (1) draw the circuit diagram of the experiment. (2) write the experimental steps. (3) write the expression of Rx. (4) in addition to the method of substitution with known resistance, You can also use switch (or single pole double throw switch), sliding rheostat to solve the unknown resistance. Students use their brains to think, can you use other methods to measure the resistance of the unknown resistance?
- 19. Explore the experiment (1) given a power supply, a voltmeter, a constant resistance (known its resistance), a number of switches and wires, try to design a circuit diagram It can measure the resistance of an unknown resistance according to certain steps You want to draw a picture for me~ In addition, the corresponding letters should be used to represent the physical quantities measured by the elder brother Represents each measured physical quantity Can you give me a picture
- 20. As shown in the figure, the power supply voltage U remains unchanged, and the indication of ammeter is 2A. Resistance R1 and R2 are in parallel, equivalent resistance R, and R1: r = 4:3, If the power consumed by resistor R2 is 2.5W. Find the power supply voltage