The consumer with resistance R is connected to the power supply, and the current passing through the consumer is I, so that the current passing through the consumer is reduced to 1 / 3 of the original. A () resistor should be connected to the consumer in series

Assuming that the power supply has no internal resistance, then: I = u / R; 1 / 3I = u / (R + R2)
So R2 = 2R

When the rated voltage of 6V is connected in series with a resistance of 4 Ω and connected to the power supply, the current of the circuit is 0.5A under normal operation
The resistance of the consumer is Ω, and the power supply voltage is V.

The resistance of the consumer is__ 12__ Ω, and the power supply voltage is__ 5__ V

Two lamps marked with "220 V & nbsp; & nbsp; 100 W" and "220 V & nbsp; & nbsp; 60 W" are connected in series in the 220 V circuit, and the power consumption ratio of the two lamps is The lamp marked "220V & nbsp; & nbsp; 100W" works normally The power consumption per hour is 1kW · H

∵ P = u2p, ∵ the ratio of resistance of "220 V & nbsp; & nbsp; 100 W" bulb to resistance of "220 V & nbsp; & nbsp; 60 W" bulb: r1r2 = u2p1, u2p2 = p2p1 = 60w100 w = 35, R2 = u2p2 = (220 V) 260 w = 1210 Ω; the current I through the bulb is equal when two bulbs are connected in series, and the ratio of power consumption of the two bulbs when they are connected in series: P1 = i2r1, i2r2 = r1r2 = 35; ∵ P = WT, ∵ marked with "220 V & nbsp; & nbsp; & nbsp; The time required for a 100W "lamp to consume 1kW · h electric energy normally: T = Wp1 = 1kW · h0.1kw = 10h

If L1 and L2 lamps marked with "220 V 100 W" and "220 V 40 W" are connected in parallel in the 220 V circuit, which lamp is brighter,

Because in series, I'm equal, W is greater if R is greater (r = P)
Therefore, the 220 V 40 W light is on

A light bulb is marked with the words of 220 V and 100 W. if you want the light bulb to light up, it means to tell you four conditions, namely, the rated voltage , rated power
The rated current is What is the resistance of the filament If it doesn't glow normally, I'll tell you a condition to pass through the filament_ For_______

The rated voltage is 220 V, the rated power is 100 W, the rated current is 5 / 11 A, the resistance is 484 ohm, no light, and the current through the filament is zero

The consumer with resistance R is connected to the power supply, and the current passing through the consumer is I, so that the current passing through the consumer is reduced to 1 / 3 of the original. A () resistor should be connected to the consumer in series