Question

Кипятильник нагревает 1.2 л воды от 12 градусов до кипения 10 мин.Определите ток потребляемый кепятильником,если он расчитан на напряжение 220 вт,КПД кипятильника 90% (с=4200Дж/кг умножанный на градус цельсия)

Answer 1

задача на закон Джоуля-Ленца $Q=I^{2}R t$

$\eta=\frac{A_{p}}{Q}100$

 

найдем полезную роботу $A_{p}=cm\Delta t$ 

затем найдем затраченую енергию  $Q=\frac{A_{p}100}{\eta}$ 

подставим в  первоеуровнение тогда сила тока равна  $I=\sqrt{\frac{A_{p}Rt100}{\eta}}$

 

 

 

 

 

 

Answer 2

Calculation of Power Consumption

To determine the current consumed by the kettle, we need to calculate the power it consumes. The power consumed by an electrical device can be calculated using the formula:

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

Given that the kettle is designed for a voltage of 220 V, we can rearrange the formula to solve for the current:

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

The power of the kettle is given as 220 W (watts). Plugging in the values, we can calculate the current consumed by the kettle:

Current (I) = 220 W / 220 V = 1 A (ampere)

Therefore, the kettle consumes a current of 1 ampere.

Calculation of Energy Required

To calculate the energy required to heat 1.2 liters of water from 12 degrees Celsius to boiling, we can use the specific heat capacity of water. The specific heat capacity of water is approximately 4200 J/kg°C.

First, we need to calculate the mass of water being heated. The density of water is approximately 1 kg/liter. Therefore, the mass of 1.2 liters of water is:

Mass (m) = Volume (V) x Density (ρ) = 1.2 kg

Next, we can calculate the change in temperature:

Change in Temperature (ΔT) = Final Temperature - Initial Temperature = 100°C - 12°C = 88°C

Now, we can calculate the energy required using the formula:

Energy (E) = Mass (m) x Specific Heat Capacity (c) x Change in Temperature (ΔT)

Plugging in the values, we get:

Energy (E) = 1.2 kg x 4200 J/kg°C x 88°C = 443,520 J

Therefore, the energy required to heat 1.2 liters of water from 12 degrees Celsius to boiling is 443,520 joules.

Calculation of Time

To determine the time taken by the kettle to heat the water, we can use the formula:

Energy (E) = Power (P) x Time (t)

Rearranging the formula to solve for time:

Time (t) = Energy (E) / Power (P)

Plugging in the values, we get:

Time (t) = 443,520 J / 220 W = 2016 seconds

Converting seconds to minutes:

Time (t) = 2016 seconds / 60 seconds/minute = 33.6 minutes

Therefore, the kettle takes approximately 33.6 minutes to heat 1.2 liters of water from 12 degrees Celsius to boiling.

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