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Whether a small light bulb emits light depends on what? Rated voltage, rated current or resistance, or rated power
With the rated voltage, the small bulb will flow through the rated current and emit normal light. At this time, the power consumed by the small bulb is the rated electric power
Lower than the rated voltage will also emit dark light, but to a certain extent, it will not emit light
When the bulb marked "220 V 40 W" works normally, what is the current passing through it? What is the resistance when it works normally?
A bulb marked with "220V 40W" is connected to the circuit. What is the current and resistance during normal operation?
If the voltage of the circuit is 110V, calculate the actual power of the bulb?
I normal = P / u = 40 / 220 = 0.182 (a); r = u ^ 2 / P = 220 * 220 / 40 = 1210 (EU);
P (110V) = 110 * 110 / 1210 = 10 (W)
After the voltage at both ends of the resistor changes from 6V to 2V, the current changes by 0.2A, then the resistance value is. The power of resistance change is w or w
Colarcer's last step was wrong
I2-I1=U2/R-U1/R=(U2-U1)/R=0.2
R = 10 ohm
When the voltage increases by 2V, the power change = U2 ^ 2 / r-u1 ^ 2 / r = 8 * 8 / 10-6 * 6 / 10 = 2.8W
If the voltage decreases by 2V, the power change = 6 * 6 / 10-4 * 4 / 10 = 2W
RELATED INFORMATIONS
- 1. When the voltage at both ends of the resistor increases from 2V to 4V, the current intensity through the resistor changes by 0.25A, Then the resistance of the constant resistance ro is____ Ohm. The electrical power of the resistance ro increases____ w. This is to fill in the blanks!
- 2. DC power supply 5V need resistance to step down to 4V, limit current in 4.5a need a few w several r resistance?
- 3. The current is 1a and the voltage is 5V. How many resistances do you need to reduce the voltage to 4, 3, 2 and 1V
- 4. What is the resistance of 3A 0.6A ammeter? What about a 3V, 15V voltmeter?
- 5. The title is "the circuit diagram of the experiment of measuring resistance by volt ampere method". In the diagram, there are ammeter (range 0 ~ 0.6A, 3a), voltmeter (range 0 ~ 3V, 15V), sliding rheostat (range of resistance value 0 ~ 12ohm), resistance Rx to be measured (about 6ohm, calculated as 6ohm) and power supply composed of three new dry batteries in series, I don't understand why the maximum current in the circuit is 0.75a, but the solution judges that the range of 0-0.6a should be selected. When the ammeter selects the range of 0-0.6, the maximum voltage at both ends of the constant resistance is 3.6V, but the solution judges that the range of 0-3v should be selected, Isn't that against the norm?
- 6. As shown in the figure, the power supply voltage remains unchanged, the range of ammeter is 0 ~ 3a, and the resistance R2 = 10 Ω
- 7. In the circuit as shown in the figure, the specifications of the two ammeters are the same. The ammeter has two ranges (0-0.6a and 0-3A). When the switch S is closed, the current flows through the resistance R1 and R2. If the pointer deflection angle of the two ammeters is the same, the ratio of R1 to R2 is () A. 1：5B. 5：1C. 1：4D. 4：1
- 8. The experimental equipment includes an ammeter with a range of (0 ~ 0.6A, 0 ~ 3a), a voltmeter with a range of (0 ~ 3V, 0 ~ 15V), a sliding rheostat (1a, 18 Ω) and a power supply (6V). If the resistance of about 6 Ω is measured with the above equipment, then: (1) in order to form the experimental circuit, in addition to the above equipment, it is necessary to______ One, at least______ (2) the range of current variation in the circuit is about______ (3) it is required that the pointer of ammeter and voltmeter should not exceed the range in the experiment, and the pointer of ammeter and voltmeter should be deviated from the middle line of the dial when measuring data for several times______ Range, voltmeter should be used______ Range
- 9. In the experiment of exploring the relationship between current and voltage, resistance, when exploring the relationship between current and resistance, we should () A. Adjust the sliding rheostat to keep the current in the circuit constant B. Adjust the sliding rheostat so that the voltage at both ends of different fixed resistor R remains unchanged C. Make the voltage at both ends of resistance R change in multiple D. The current in the circuit should be changed in multiple during each measurement
- 10. The resistor R1 and R2 are connected in series on the power supply with a voltage of 4.5V. The resistance of R1 is known to be 5 Ω, and the voltage at both ends of R2 is 3V. The total resistance in the circuit and the total resistance through R2 are calculated The resistance of an electric bell is 10 Ω. When it works normally, the voltage at both ends is 4V. Now it is connected to 9V power supply. In order to make it work normally, how much resistance should it be connected in series?
- 11. When exploring the relationship between the current and voltage on the resistance, the sliding rheostat changes the voltage at both ends of the light bulb, while the book says that the voltage of the small light bulb is larger, There's a lot of current in the circuit, but I feel it doesn't matter
- 12. How to find the resistance of light bulb?
- 13. A light bulb and a sliding rheostat are connected in parallel in a circuit to increase the resistance of the sliding rheostat. Does the light bulb turn on or dark?
- 14. To enable the rheostat to control the brightness of the bulb, should the rheostat be connected in series or in parallel with the bulb It controls the brightness of the light bulb
- 15. Without changing the power supply voltage, please design a circuit diagram to change the brightness of the bulb
- 16. The bulb and a resistor are connected in series to the power supply. The power of the lamp is 81w, and the power of the resistor is 9W. If the lamp is directly connected to the power supply, it will light normally Calculate the rated power of the lamp
- 17. 1. Two resistors with the same organization are connected in series first and then in parallel, respectively in the circuit with the same voltage. What is the ratio of the total power of series and parallel?
- 18. In order to explore the "relationship between electric power and resistance", Li Ming found two lamps L1 and L2 with the rated voltage of 6V. He connected the two lamps in series and started the experimental exploration according to the circuit shown in the figure. After closing the switch, he saw that the lamp L2 was slightly luminous, while the lamp L1 was almost not luminous. Then the relationship between the resistance R1 and R2 of the two lamps, and the rated power P1 and P2 of the two lamps was established (not applicable) Consider the change of filament resistance value with temperature) () A. R1＞R2，P1＞P2B. R1＜R2，P1＜P2C. R1＞R2，P1＜P2D. R1＜R2，P1＞P2
- 19. A light bulb is marked with "4V, 4W". After it is connected in series with a constant resistance R, it is connected into the circuit with the power supply voltage of 6V. When the switch is closed, measure the A bulb is marked with the words "4V, 4W". After it is connected in series with a constant resistance R, it is connected to the circuit with the power supply voltage of 6V. When the switch is closed, the measured power consumption of R is 2W. At this time, the bulb does not light normally. Regardless of the influence of temperature on the resistance value of the bulb, calculate: 1 the resistance value of the constant resistance R, 2 the incident electric power of the bulb
- 20. The lamp and a resistor R are connected in series and then connected in a circuit with voltage of U. the current flowing through the lamp is I, and the electric power consumed by the lamp is?