The electric iron is designed for a voltage of 220 V. The resistance of its heating element is 88 ohms. Determine the energy consumed by the iron in 30 minutes and its power.
Initial data: U (voltage for which the taken electric iron is designed) = 220 V; R (heating element resistance) = 88 ohms; t (duration of the taken electric iron) = 30 min (1800 s).
1) The power of the electric iron taken: P = U2 / R = 220 ^ 2/88 = 550 W.
2) Consumed energy in 30 minutes: Q = U ^ 2 * t / R = P * t = 990,000 J (990 kJ).
Answer: The power of the electric iron taken is 550 W; electricity consumption for 30 minutes is 990 kJ.
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