The electric stove is connected to a current source with a voltage of 220 V. For 20 minutes. it emits an amount of heat equal

univerkov | December 1, 2020 | education

The electric stove is connected to a current source with a voltage of 220 V. For 20 minutes. it emits an amount of heat equal to 1.05 MJ. Determine the current strength, power of the stove and the cost of consumed electricity (tariff – 1.60 lei / kW * h.)

Given: | CI
U = 220V | 20 minutes = 1200 seconds
t = 20 min |
Q = 1050000J |

Decision:
Q = I ^ 2R * t
I = U / R
Q = (U ^ 2 / R) * t,
R = (U ^ 2t) / Q = (220 ^ 2 * 1200) / 1050000 = 55.3 ohms.
I = u / R = 220: 55.3 = 4A
P = UI = 220 * 4 = 880W
Answer: 880 W

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