Lag1989 problem number 15.9

Lag1989 problem number 15.9

There is a light bulb with voltage U = 120 V, power P = 40 W. What additional resistance R should be connected in series with a light bulb so that it gives a normal glow at a voltage of U₀ = 220 V? How many meters of L nichrome wire with a diameter of d = 0.3 mm must be taken to get such resistance?

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