Question

Нагреватель нагривает 1 литр воды до 20 градусов за 20 минут , КПД 70%, 220В , Найти R-? Сопротивление ​

Answer 1

Ответ:

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Answer 2

Calculation of Resistance (R) in a Heater

To find the resistance (R) of the heater, we need to use the formula:

R = (V^2) / (P × η)

Where: - R is the resistance of the heater, - V is the voltage (220V in this case), - P is the power (in watts) consumed by the heater, - η is the efficiency of the heater (70% in this case).

To calculate the power consumed by the heater, we can use the formula:

P = (m × c × ΔT) / t

Where: - P is the power consumed by the heater, - m is the mass of water (1 liter, which is equivalent to 1 kilogram), - c is the specific heat capacity of water (4.186 J/g°C), - ΔT is the change in temperature (20°C), - t is the time taken to heat the water (20 minutes, which is equivalent to 1200 seconds).

Let's calculate the power consumed by the heater first:

P = (1 kg × 4.186 J/g°C × 20°C) / 1200 s

Using the given values, we can calculate the power consumed by the heater.

P = (1 kg × 4.186 J/g°C × 20°C) / 1200 s = 0.06977 J/s = 69.77 W

Now, let's calculate the resistance (R) of the heater using the formula mentioned earlier:

R = (V^2) / (P × η)

Substituting the given values:

R = (220V^2) / (69.77 W × 0.7)

Calculating this expression will give us the value of resistance (R) for the heater.

Please note that the specific values for the power consumed by the heater and the resistance of the heater may vary depending on the specific characteristics of the heater being used.