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Three bulbs with different rated power and voltage are connected to the 220 V circuit respectively. Which bulb is brighter or the same? (please explain the reason)
If it is connected separately, of course, the one with higher power will be brighter. If it is three connected in series, the one with lower power will be brighter
Two lamps marked with "220 V 40 W" are connected in series and then connected in a 220 V circuit. The sum of the actual power of the two lamps is（
Resistance of 220 V, 40 W lamp: r = u ^ 2 / P = 220 * 220 / 40 = 1210 Ω
Series resistance = 2 * r = 2 * 1210 = 2420 Ω
Power sum = 220 * 220 / 2420 = 20W
What grade are you in?
1、 If a small bulb marked with "220 V 40 W" is connected to both ends of the lighting circuit, what is its actual power? If the voltage at both ends is 110 V, what is the actual power of the lamp? How will the two degrees of the lamp change?
2、 Connect a and B bulbs marked with "6V 3W" and "6V 6W" in series to 9V power supply, (1) what are their actual power and (2) which lamp is on?
1 connected to both ends of the lighting circuit, its actual power is "40W". When the voltage at both ends is 110V, it is known from "P = u ^ 2 / R". When the lamp resistance is constant, the lamp power P is directly proportional to the square of the voltage U. therefore, the actual power is 40 * (1 / 4) = 10W, and the brightness becomes dark. The resistance of 2a is R1 = u ^ 2 / P = 36 / 3 = 12 Ω, and the resistance of 2b is R2 = 36 / 6 = 6 Ω
The voltage is 220 V, 50 Hz, 10 A, how many watts is the power?
P=UI=220×10=2200w
RT. electrical power of household appliances marked with "220 V 40 W" in normal operation ()
A. More than 40 watts B. less than 40 watts C. equal to 40 watts D. equal to 220 watts
C
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