Our electricity bills consist of many different forms of energy use. In order to be able to make estimates
on how much different appliances use electricity and how much savings could be done by investing less
electricity consuming ones, you need to have understanding on electricity calculations.
Solve the calculations below:
An electric heater of power 2500 W is connected to a voltage of 230 V.
i) Calculate the electric current going through the heater.
ii) What is the resistance of the heater?
iii) How much energy does it consume in a year, if it is switched on 15 min every day.
iv) How much it costs per year to use the heater when the price of electricity is 0,0479 €/kWh?
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i) To calculate the electric current going through the heater, you can use Ohm's Law, which states that the current (I) is equal to the voltage (V) divided by the resistance (R). In this case, you have the power (P) of the heater, but you need to find the current (I).
Using the formula: P = V * I, you can rearrange it to solve for current: I = P / V.
Thus, the equation becomes: I = 2500 W / 230 V = 10.87 Amps.
Therefore, the electric current going through the heater is approximately 10.87 Amps.
ii) To find the resistance of the heater, you can use Ohm's Law again. Rearrange the formula to solve for resistance: R = V / I.
In this case, the resistance will be: R = 230 V / 10.87 Amps = 21.18 Ohms.
So, the resistance of the heater is approximately 21.18 Ohms.
iii) To calculate the energy consumed in a year by the heater, you first need to find out how much energy it uses per day. The power (P) of the heater is given as 2500 W, which means it consumes energy at a rate of 2500 W per hour.
Since it is used for 15 minutes (0.25 hours) every day, the energy consumed per day is: 2500 W * 0.25 hours = 625 Wh (watt-hours).
Since there are 365 days in a year, you can multiply the daily consumption by the number of days: 625 Wh/day * 365 days = 228,125 Wh.
iv) To calculate the cost per year to use the heater, you need to convert the energy consumption from watt-hours (Wh) to kilowatt-hours (kWh), as the price is given in euros per kilowatt-hour.
To convert Wh to kWh, divide the energy consumption by 1000: 228,125 Wh / 1000 = 228.125 kWh.
Now, multiply this by the price of electricity per kWh: 228.125 kWh * 0.0479 €/kWh = 10.93 €.
So, it would cost approximately 10.93 € per year to use the heater if the price of electricity is 0.0479 €/kWh.