Question

Кипятильник нагревает одну целую две десятых килограмма воды от 12 градусов до кипения за 10 минут Определите ток кипятильника если он рассчитан на напряжение 220 вольт КПД равно 90%

Answer 1

Найдём затраты тепла: Q=C*m(t2-t1)=4200кал*1.2л(100-10)=453600Дж
Выразим затраты тепла через работу эл.тока:
W=U*I*t    453600=220*I*600c   при кпд=100% достаточно было бы времени 600с*0.9=540с   это значит, что мощность Р=U*I=220*I*=840вт
ток I=W/118000=3.81a        где 118000=220в*540с
ответ:ток кипятильника =3.81а

Answer 2

Calculation of the Power of the Immersion Heater

To determine the current of the immersion heater, we need to calculate the power (P) of the heater first. The power can be calculated using the formula:

P = (m * c * ΔT) / t

Where: - P is the power in watts (W) - m is the mass of water in kilograms (kg) - c is the specific heat capacity of water, which is approximately 4.186 J/g°C or 4186 J/kg°C - ΔT is the change in temperature in degrees Celsius (°C) - t is the time taken to heat the water in seconds (s)

In this case, we are given: - m = 0.2 kg (one whole two-tenths of a kilogram) - ΔT = 100°C (from 12°C to boiling point) - t = 10 minutes = 600 seconds

Let's calculate the power of the immersion heater using these values:

P = (0.2 kg * 4186 J/kg°C * 100°C) / 600 s

Calculating this expression gives us the power of the immersion heater.

Calculation of Current

To calculate the current (I) of the immersion heater, we can use the formula:

P = V * I

Where: - P is the power in watts (W) - V is the voltage in volts (V) - I is the current in amperes (A)

In this case, we are given: - V = 220 V (voltage) - P (power) is the value we calculated earlier

Let's calculate the current of the immersion heater using these values:

I = P / V

Calculating this expression gives us the current of the immersion heater.

Calculation with Efficiency

The given problem also states that the efficiency (η) of the immersion heater is 90%. Efficiency is defined as the ratio of useful output energy to the input energy. In this case, the useful output energy is the heat energy transferred to the water, and the input energy is the electrical energy consumed by the heater.

The efficiency can be calculated using the formula:

η = (useful output energy / input energy) * 100%

In this case, the input energy is equal to the power (P) of the immersion heater, and the useful output energy is the heat energy transferred to the water.

To calculate the current of the immersion heater with efficiency taken into account, we can modify the previous formula:

I = (P / V) * (100% / η)

Calculating this expression gives us the current of the immersion heater, taking into account the efficiency.

Now, let's calculate the current of the immersion heater using the given values and formulas.