![](data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" viewBox="0 0 72 71" width="72"></svg>)
There is a small light bulb, when it is connected in series with a 40 ohm resistor and connected to a 6 V power supply, it can light normally. The small light bulb can light normally for 5 seconds, and the current works for 1 joule Calculate the rated voltage of the small bulb,
According to P = w / T, the rated power of the bulb is P1 = 1J / 5S = 0.2W
Since it is connected in series with a 40 ohm resistor, the lamp current is I1 = I2 = I, U1 + U2 = u = 6V (I and u represent total current and total voltage respectively)
According to P = UI, the power of the bulb P1 = u1i1 = (6-u2) I1 = (6-u2) I = (6-ir2) I = (6-ir2) U / (R1 + R2) = [6 - (U / (R1 + R2) R2] U / (R1 + R2) = [6 - (6 / (R1 + 40) 40] 6 / (R1 + 40) = 0.2W
The solution is R1 = 20 or 80 Ω
According to P = u ^ 2 / R, the
When R1 = 20 Ω, rated voltage U1 = √ 0.2W × 20 Ω = 2V
When R1 = 80 Ω, rated voltage U1 = √ 0.2W × 80 Ω = 4V
In a 220 volt circuit, the current passing through the bulb is 68 ma. What is the power of the bulb? A total of one month
Resistance = 220 / 0.068 = 3235.3 ohm, the electric power of the bulb is the square of the current multiplied by the resistance
P=0.068*0.068*3235.3=14.96W
Power on T = 100 hours = 100 * 3600 = 360000s, so the work done by current w = Pt = 5385600 joules, equal to 1.496 kwh
The bulb marked with "220 V 40 W" works under the rated voltage. How many joules does the current work when it passes through one bank? How many joules does the current work when it passes through the lamp every minute
W=UIt=UQ=220V*1C=220J
Passing the light every minute?
RELATED INFORMATIONS
- 1. When a small bulb is electrified for 2 minutes, it consumes 240 J of electric energy. Please draw the circuit diagram to calculate the electric power of the lamp
- 2. 1. A lamp consumes 1kW of electricity in 25 hours. What is the power of this lamp? 2. How many hours can a 220V 50W bulb work with 1000W of electricity 1. A lamp consumes 1kW in 25 hours. What is the electric power of this lamp? 2. How many hours can a 220V 50W bulb work with 1000W electric energy? (detailed solution process and formula are required) 3. How much energy is consumed by a 110 V, 100 W electric appliance working for one hour? If the power ratio of a and B dual-purpose electrical appliances is 4:1 and the power on time ratio is 2:1, what is the power consumption ratio?
- 3. 220 V power supply is connected in series with a 25 W bulb and a 40 W bulb. The actual power of the last two lamps is calculated and the calculation formula is listed
- 4. There is an electric lamp, which consumes 100 watts when connected to the power supply. Connect it in series with another resistor and then connect it to the same power supply. The power consumed by the resistor is 9 watts. The strategy of bulb consumption at this time is proposed
- 5. The bulb L1 of "pz220-40" and the bulb L2 of "pz220-100" are connected in series in a 220 V circuit to calculate the actual power of the two lamps and compare which lamp is brighter? The bulb L1 of "pz220-40" and the bulb L2 of "pz220-100" are connected in series in a 220 V circuit to calculate the actual power of the two lamps and compare which lamp is brighter?
- 6. There is a bulb with a resistance of 15 ohm. When the two ends of the bulb are applied with a voltage of 6 V, the bulb can work normally. If the bulb is connected to a 7.5 V power supply, it will still light normally. What is the resistance of the bulb in series?
- 7. For the parallel resonant circuit of inductor coil and capacitor, the higher the resistance is, the higher the power factor is, and the higher the quality factor is（
- 8. When the power supply voltage remains unchanged and the resistance of a resistor increases by 3 ohm, the current intensity becomes four fifths of the original?
- 9. Rated at 100 v. can a 10 W power supply guarantee the proper operation of a 2K ohm resistor rated at 100 V?
- 10. It is known that the resistance of a small light bulb is 20 ohm when it normally emits light, and the current passing through is 0.5 A. then the voltage at both ends of the small light bulb when it emits light is 0______ If the voltage of the power supply is 16 V, in order to make the small light bulb shine normally, one should be connected in series______ Ohm resistance
- 11. The bulb marked 12v6w is connected in series with a 36 ohm resistor on a 12V power supply. What is the actual power of the bulb? What is the power consumed by the resistor at this time?
- 12. A 5V 2W bulb L is connected in series with a 10 ohm resistor R1, and then connected to a stable voltage power supply. The lamp l will light normally L and resistor R2 are connected in series and connected to the same power supply. The power of bulb L is 0.5W. Calculate the resistance of R2
- 13. The bulb marked "6V & nbsp; 3W" is connected in series with an 18 ohm resistor and connected to a 9V power supply. What is the actual power of the bulb?
- 14. When a bulb works normally, the voltage is 12 V and the resistance is 24 Ω. If the power supply voltage is 36 V, in order to make the bulb work normally, it is necessary to When a bulb works normally, the voltage is 12 V, and the resistance is 24 Ω. If the power supply voltage is 36 V, in order to make the bulb work normally, what is the resistance in series?
- 15. The voltage is 12 V and there is one 3mm diode. How much resistance do you need? How much resistance do you need for three diodes?
- 16. How big is the resistance of 5 white LEDs in parallel 12V battery? Repair a small lamp. The resistance is burned
- 17. In the circuit shown in the figure, R1 = 30 Ω, R2 = 10 Ω. After the switch S is closed, the indication of ammeter A is 0.4A. Calculate the power supply voltage, the current through R2 and the current in the main circuit
- 18. A physics problem: there are four resistances, R1 = 1, R2 = 2, R3 = 3, R4 = 4, e = 4V, r = 0.2, total current ——R1——R3—— | | | ——R2——R4—— | | ——||————— R1 and R3 are in one branch, R2 and R4 are in one branch, that is to say, they are connected in series and then in parallel, and there is another line between R1 and R3 and between R2 and R4 The general circuit diagram is like this. The lines in the diagram are all connected Is the middle line useless?
- 19. Why is it that if the voltage indication number is zero, the circuit of the measured part is short circuited
- 20. What is the electromotive force of the power supply equal to the voltage between the two poles of the power supply when the power supply is open Such as the title Why is it not the voltage between the two poles of the power supply when the circuit is connected?