A water heater marked 4 kW takes 4 minutes to heat 1 kg of water from 20 °C to 50 °C. The cost of electrical energy per kWh
is $0.120. What will be the total cost of energy consumption?

Respuesta :

The total cost of the energy consumption for the given time period is $0.0364

The given parameters include;

  • power rating of the heater, P = 4 kW = 4000 W
  • time taken to completely boil the water,[tex]t = 4 \min = 4 \min \times \frac{1 \ h}{60 \ \min} = 0.067 \ h[/tex]
  • mass of the water, m = 1 kg
  • initial temperature of the water, t₁ = 20 ⁰C
  • final temperature of the water, t₂ = 50 ⁰C
  • specific heat capacity of water, c = 4200 J/kg⁰C
  • cost of electrical energy = $0.12

The total energy consumed in the process of heating the water;

Total electrical Energy  = Energy of the heater (kWh) + Energy of the heated water (kWh)

Energy of the heater (kWh) = power x time

                                = 4 kW x 0.067 h

                                 = 0.268 kWh

Energy of the heated water (J) = mcΔt

where;

Δt is the change in temperature = t₂ - t₁

                                                      = 50 ⁰C  -  20 ⁰C = 30⁰C

Energy of the heated water (J) = 1 x 4200 x 30

                                               = 126,000 J

Electrical power of the heated water (Watts) = [tex]\frac{126,000 \ J}{4 \ \min} \times \frac{1 \min}{60 \ s} = 525 \ W[/tex]

Energy of the heated water (kWh) = [tex]\frac{525}{1000} \times 4\min\times \frac{1 \ hr}{60 \min} = 0.035 \ kWh[/tex]

Total electrical Energy  = 0.268 kWh  +  0.035 kWh

                                       = 0.303 kWh

The total cost of the energy consumed is calculated as;

[tex]Total \ cost = \frac{\$ \ 0.12}{kWh} \times 0.303 \ kWh = \$ \ 0.0364[/tex]

Therefore, the total cost of the energy consumption is $0.0364

To learn more about cost of electrical energy calculation, please visit: https://brainly.com/question/17924004