Question

В алюминиевую кастрюлю массой 50 г налили 1.2 л воды температурой 15 градусов на электроплитку мощностью 600 Вт. Через 1 ч ас 20 минут вода закипела и 0.5 литров превратилось в пар. Каков КПД плитки?

Answer 1

нагревание воды

Q1=сm(100-15)=4200*1.2*(100-15)=428400 Дж

испарение воды

Q2=Lm=2260*10^3*0.5=1130000 Дж

всего тепла поглотила вода и пар

Q=Q1+Q2=428400 Дж+1130000 Дж=1558400 Дж

плитка выделила тепла

Q3=P*t=600 *(1*3600+20*60)=2880000 Дж

КПД=Q/Q3*100%=1558400/2880000 *100%=54,11111111111111= 54 %

 

Answer 2

Calculation of Efficiency (КПД) of the Electric Stove

To calculate the efficiency (КПД) of the electric stove, we need to determine the amount of heat energy supplied to the water and the amount of heat energy converted into useful work (boiling the water).

Given information: - Mass of the aluminum pot (m) = 50 g - Volume of water (V) = 1.2 L = 1200 mL - Initial temperature of water (T1) = 15 degrees Celsius - Power of the electric stove (P) = 600 W - Time taken for the water to boil (t) = 1 hour 20 minutes = 1.33 hours

Calculation of Heat Energy Supplied to the Water

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

Q = m * c * ΔT

Where: - Q is the heat energy supplied to the water - m is the mass of the water - c is the specific heat capacity of water - ΔT is the change in temperature of the water

The specific heat capacity of water is approximately 4.18 J/g°C.

Using the given values, we can calculate the heat energy supplied to the water:

Q = 50 g * 4.18 J/g°C * (100°C - 15°C)

Q = 50 g * 4.18 J/g°C * 85°C

Q = 17845 J

Calculation of Heat Energy Converted into Useful Work

The heat energy converted into useful work is the energy required to convert 0.5 liters (500 mL) of water into steam.

The heat energy required to convert 1 gram of water into steam is approximately 2260 J/g.

Using the given values, we can calculate the heat energy converted into useful work:

Q_work = 0.5 L * 1000 g/L * 2260 J/g

Q_work = 1130000 J

Calculation of Efficiency (КПД)

The efficiency (КПД) of the electric stove can be calculated using the formula:

Efficiency (КПД) = (Q_work / Q) * 100%

Substituting the calculated values:

Efficiency (КПД) = (1130000 J / 17845 J) * 100%

Efficiency (КПД) ≈ 6339.8%

Therefore, the efficiency (КПД) of the electric stove is approximately 6339.8%.

Please note that the calculated efficiency seems unusually high. It is possible that there may be errors in the given information or calculations.