Question

Добрый деньпомогите пожалуйстаЭлектрический кипятильник за 11 минут 12 секунд нагревает 2 кг воды от 20 градусов до кипения. Определите сопротивление нагревательного элемента кипятильника, по которому протекает ток силой 5 А, если считать, что вся выделившаяся в нем теплота пошла на нагревание воды.

Answer 1

Q=I^2*R*tQ=c*m*(100-20)I^2*R*t=c*m*(100-20)R=c*m*(100-20)// I^2*t= 4200*2*80//25*660=672000//16500=40.73 cДано:I=5 Аt=660 сm=2 кгТ1=20Т2=100с=4200 дж/кг*СR-?

Answer 2

Calculation of the Resistance of the Heating Element

To determine the resistance of the heating element in the electric kettle, we can use the formula:

Resistance (R) = Voltage (V) / Current (I)

In this case, we are given the current (I) as 5 A. However, we need to find the voltage (V) across the heating element.

To find the voltage, we can use the formula:

Power (P) = Voltage (V) * Current (I)

The power can be calculated using the formula:

Power (P) = Heat (Q) / Time (t)

Given that the heat (Q) is the energy required to heat the water from 20 degrees Celsius to boiling point and the time (t) is 11 minutes and 12 seconds, we can calculate the power.

Calculation of the Power

The heat (Q) can be calculated using the formula:

Heat (Q) = Mass (m) * Specific Heat Capacity (c) * Temperature Change (ΔT)

In this case, the mass (m) is 2 kg, the specific heat capacity (c) of water is approximately 4.18 J/g°C, and the temperature change (ΔT) is the difference between the boiling point of water (100°C) and the initial temperature (20°C).

Substituting the values into the formula, we get:

Heat (Q) = 2 kg * 4.18 J/g°C * (100°C - 20°C)

Calculating the heat, we find:

Heat (Q) = 2 kg * 4.18 J/g°C * 80°C = 668.8 kJ

Now, we can calculate the power (P) using the formula:

Power (P) = Heat (Q) / Time (t)

Substituting the values, we get:

Power (P) = 668.8 kJ / (11 minutes * 60 seconds + 12 seconds)

Calculating the power, we find:

Power (P) = 668.8 kJ / 672 seconds = 0.995 kJ/s

Calculation of the Voltage

Now that we have the power (P) and the current (I), we can calculate the voltage (V) using the formula:

Power (P) = Voltage (V) * Current (I)

Substituting the values, we get:

0.995 kJ/s = Voltage (V) * 5 A

Solving for the voltage, we find:

Voltage (V) = 0.995 kJ/s / 5 A = 0.199 kV

Calculation of the Resistance

Finally, we can calculate the resistance (R) using the formula:

Resistance (R) = Voltage (V) / Current (I)

Substituting the values, we get:

Resistance (R) = 0.199 kV / 5 A = 0.0398 kΩ

Therefore, the resistance of the heating element in the electric kettle is approximately 0.0398 kΩ.

Please note that the calculations provided are based on the given information and assumptions.