For non pure resistance circuit, can p = UI be used to calculate electric power? Why? P = u / R? Isn't P = UI a universal formula? Is it OK?

For a non pure resistance circuit, to calculate the electric power of the whole circuit, the product of the voltage loaded in the circuit and the current of the whole trunk circuit should be used. If u ^ 2 / R is used, it is not suitable. Because the circuit is not pure resistance circuit, other electrical appliances with other capacitors or something are actually equal to resistance

If you want to connect an electrical appliance marked with "110V, 20W" into a circuit with voltage of 220V, how much resistance must be connected in order to make the electrical appliance work normally, and how to connect the circuit

Using u ^ 2 / P, the resistance of the consumer is 605 ohm, and then a 605 ohm resistor can be used to divide the voltage, so a 605 ohm resistor is connected in series

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1. What is the actual power of a 220 V, 44 w appliance used in a 110 V circuit
2. If there is a 20 ohm resistor and the power consumed within 30 minutes is 1 kW. H, what is the current through the resistor
3. The resistance of a conductor is 2 Ω. How many joules of heat are generated in one minute when the current is 2A?
4. The maximum current that a resistance wire can pass is 2A. When a voltage of 36V is applied to it, the current passing through is 0.5A______ (fill in "can" or "can't") used in 220 V circuit
5. In the circuit shown in the figure, the resistance value of resistance R1 is 15 Ω, the resistance value of resistance R2 is 10 Ω, and the current through resistance R1 is 0.2 a
6. Resistor R1 and R2 are connected in series in the circuit, the voltage at both ends of R1 is 3V, the voltage at both ends of R2 is 9V, R1 + R2 = 600 Ω (1) total current and voltage (2) current in the circuit (3) resistance value of resistance R1 and R2
7. In the circuit as shown in the figure, the resistance R1 = 8ohm, R2 = 10ohm, the supply voltage and the resistance of the constant resistance R are unknown. When the switch S is connected to 1, the current representation is 0.2 When the switch S is connected to 2, the possible value of current expression number is between () a and () A. please explain the analysis process, There is no way to send the figure. It is like this: when the switch is connected to 1, the resistance R1 is in series with the constant resistance R; when the switch is connected to 2, the resistance R2 is in series with the constant resistance R. in both States, the ammeter is in series with the constant resistance
8. 6. In the circuit shown in Figure 2, the internal resistance of the power supply can not be ignored. It is known that the setting resistance R1 = 10 Ω, R2 = 8 Ω. When the single pole double throw switch S is placed in position 1
9. In the circuit shown in the figure, R1 = 20 Ω, the total resistance of the circuit is 12 Ω, and the current representation is 0.3A. Please calculate: (1) resistance value of resistance R2; (2) power supply voltage; (3) current through R2
10. Resistance R1: R2 = 2:3, connected in parallel in the circuit, the current through R1 is 3a, what is the total current? If they are connected in series, what is the current in R1?
11. In home circuit, what is the connection between fuse and electrical appliances? Mixed couplet or cross couplet The voltage of home circuit is 220 V, can fuse divide some voltage? So the voltage of electrical appliances is not 220 V?
12. Three resistors are all 10 megohm in parallel. What is the total equivalent resistance?
13. What happens when the resistance is 0? If the resistance in the circuit is a few ohm, according to Ohm's law, will the current increase?
14. How many ohms is the resistance of the lamp marked with pz220-100? If it is connected to a 110V circuit, how many watts is the actual power?
15. A light bulb is printed with "PZ & nbsp; 220 & nbsp; & nbsp; 40". How much resistance does it have when it works normally? If it is connected to a 110V circuit, what is the actual power consumption?
16. A and B bulbs are respectively marked with the words "220 V 40 W" and "220 V 60 W", which are connected in parallel with the 220 V power supply. What is the resistance of B
17. 60W / 220V AC incandescent lamp is connected with diodes in series, and then connected with 220V AC power supply, the power consumption is ()
18. How to connect the 100W, 60W and 40W bulbs with the rated voltage of 110V in the circuit with the power supply voltage of 220V to make the bulbs light normally? Draw the circuit diagram and explain the reason with simple calculation
19. After a 110V, 100W light bulb is connected in series with a 100V, 40W light bulb, it can be connected to the 220V circuit to judge whether the problem is right or wrong
20. Resistor R1 and R2 are connected in parallel in the circuit. The voltage applied at both ends is 24 v. if R1 is 80 Ω, the current through R2 is 0.2 a, and R2 is calculated?