How many hours can the light bulb marked with "220 V 40 W" work normally with 1000 watt hour power?

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• 1. Some problems about "electric power calculation" I always confuse P = UI and P = u ^ 2 / R when solving the calculation of electric power I don't know which formula to use Please master advice: under what circumstances. With P = UI calculation Under what circumstances is p = u ^ 2 / r used to calculate ``` Add. These seem to relate to what the actual power rating is.
• 2. Examples are given to illustrate the meaning of the word
• 3. Give an example of the meaning in this word
• 4. The meaning of "Ju" in ancient Chinese is the same, with examples
• 5. What does it mean to draw inferences from one instance?
• 6. Characteristics and examples of classical Chinese
• 7. The anecdotes of sun Tai in classical Chinese reflect the truth Sun Tai, a native of Shanyang and a young teacher of huangfuying, is very virtuous. His wife is his aunt. First, his aunt is old, and he asks his two sons to marry his younger brother. Then, his aunt dies, and Tai marries his elder sister. Or, he asks, Tai says, "if he has a disease, it's not suitable for him." This is the original text. May I ask you, prawns, what kind of ideological quality does these two things reflect? Prawns, although less points, (I did not point) but fast, fast words will increase
• 8. Stories in classical Chinese
• 9. This paper analyzes the historical and practical significance of "the ancient scholars are for themselves and the present scholars are for people"; There is also an analysis of the historical and practical significance of "in the Analects of Confucius, if the father is present, he will observe his ambition; if the father is absent, he will observe his behavior; if he has not changed his way in three years, he can be called filial piety."
• 10. In the articles you have read in the past, which people have the heart of ancient benevolence? Give two examples and briefly explain them (except Fan Zhongyan)
• 11. The ammeter series connected with a resistor is refitted into a voltmeter. Why does the indication mean the voltage? What is the principle?
• 12. Two constant value resistors R1 and R2 (R1 "R2) are connected in series and connected to the power supply with voltage of u, with power of P1 and P2 respectively, and then connected to the power supply with constant voltage, with power of P1 * and P2 *, then () A P1 *, P1 + P2 B P1 *, P1 and P1 *, P2 C P1 * P1 and P1 * P2 D P1 * = P1 and P1 * = P2 Big brother and big sister will come and help me. I'm in a hurry. Big brother and big sister will come and help me. I'm in a hurry. Has anyone seen the high school entrance exam
• 13. 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
• 14. The price of type a refrigerator sold in shopping malls is 2190 yuan per unit, and the daily power consumption is 1 degree, while the price of type B energy-saving refrigerator is 10% higher than that of type a refrigerator, but the daily power consumption is 0.55 degree? (calculated according to the service life of 10 years, 365 days per year and 0.40 yuan per kilowatt hour)
• 15. The physical symbol of resistance? What is the physical symbol of resistance?
• 16. The resistance of the small bulb is about 8 Ω, the power supply voltage is 1.5V, and the range of the ammeter is 0-0.6a
• 17. Experiment on the relationship between current and voltage resistance To explore the relationship between current and voltage is to control the conductor resistance unchanged, and use sliding rheostat to change the voltage. However, when the sliding rheostat resistance is increased, the total resistance in the circuit will be increased, and the current will be naturally small. How can we know that it changes with the voltage There is also why not directly use the ammeter and voltmeter to measure the current and voltage of the sliding rheostat, so that the power supply voltage does not change, but you can change the resistance value through the jumping rheostat, and then measure the relationship between the current and resistance. Is it because the circuit can not be protected
• 18. What is the difference and function between inductance and resistance and capacitance?
• 19. A bulb with a normal working voltage of 12V has a resistance of 30ohm. Now there is only a group of batteries with a voltage of 24V. How much resistance should be connected in series to the bulb? Second question: do you have any better way?
• 20. The rated power of a clothes dryer with voltage of 220 V and 50 Hz is 1000 W. how many kilowatts of electricity do you need in three hours