Question

Электрочайник 220в, сила тока 12А, КПД чайника 80%, Определить массу воды которую можно нагреть от 0 град докипения за счетэнергии полученной на протяжении 10мин. Взять во внимание, что 1% масси води преходит в пар. удельная темплоемкость воды 4200 дж/кг*с, удельная теплота парообразования води 2 Мдж/кг

Answer 1

P*t*КПД/100%=m*((T2-T1)*Cвод+(1/100)*Спарообр)
m=P*t*КПД/100% / ((T2-T1)*Cвод+Спарообр/100) = U*I*t*(КПД/100%)/((T2-T1)*Cвод+Спарообр/100) = 220*12*10*60*(80/100)/((100-0)*4200+2000000/100) кг = 2,88 кг - это ответ

Answer 2

Calculation of the Mass of Water that can be Heated

To calculate the mass of water that can be heated from 0 degrees Celsius to boiling point using the energy obtained over a period of 10 minutes, we need to consider the power of the kettle, the efficiency of the kettle, and the specific heat capacity and latent heat of vaporization of water.

Given information: - Electric kettle: 220V, current of 12A, efficiency of 80%. - Specific heat capacity of water: 4200 J/(kg·°C). - Latent heat of vaporization of water: 2 MJ/kg.

To calculate the mass of water, we can use the formula:

Energy = Power × Time

The power can be calculated using the formula:

Power = Voltage × Current

Let's calculate the power of the kettle first:

Power = 220V × 12A = 2640W

Now, let's calculate the energy consumed by the kettle in 10 minutes:

Energy = Power × Time = 2640W × 10 minutes = 26,400 J

To determine the mass of water that can be heated, we need to consider the energy required to heat the water from 0 degrees Celsius to boiling point and the energy required to vaporize the water.

The energy required to heat the water can be calculated using the formula:

Energy = Mass × Specific Heat Capacity × Temperature Change

The temperature change is the difference between the boiling point of water (100 degrees Celsius) and the initial temperature (0 degrees Celsius).

The energy required to vaporize the water can be calculated using the formula:

Energy = Mass × Latent Heat of Vaporization

Since 1% of the mass of water is converted into steam, we can write:

Energy = 0.01 × Mass × Latent Heat of Vaporization

Now, let's solve the equations to find the mass of water:

26,400 J = Mass × 4200 J/(kg·°C) × (100 - 0)°C + 0.01 × Mass × 2 MJ/kg

Simplifying the equation:

26,400 J = Mass × 420,000 J/kg + 0.01 × Mass × 2,000,000 J/kg

Combining like terms:

26,400 J = Mass × (420,000 J/kg + 20,000 J/kg)

26,400 J = Mass × 440,000 J/kg

Solving for Mass:

Mass = 26,400 J / 440,000 J/kg

Mass = 0.06 kg

Therefore, the mass of water that can be heated from 0 degrees Celsius to boiling point using the energy obtained over a period of 10 minutes is approximately 0.06 kg.

Please note that this calculation assumes ideal conditions and does not take into account any heat losses or other factors that may affect the actual heating capacity of the kettle.