Question

In a house, three tube lights each of$40W$, two electric bulbs each of $100W$ and a fridge of $500W$ runs six hours daily. What is the consumption of electric units in a house in a month? Calculate also the cost of electricity consumed in a month if the cost of electricity for a unit is $Rs2$.

Answer 1

Step 1: Given data:

$$\begin{gathered} \text{Power of tubelight}=40W \\ \text{Power of electric bulb}=100W \\ \text{Power of fridge}=500W \\ \mathrm{Time}=6\text{hours in a day} \end{gathered}$$

Step 2: Finding the total power consumed in kW.

Power consumed by three tube light $=3\times 40$

$=120W$

Power consumed by two electric bulb $=2\times 100$

$=200W$

Power consumed by the fridge $=500W$

$$\begin{gathered} Netpower=120+200+500 \\ =820W \\ =0.82kW \end{gathered}$$

Step 3: Finding the total energy consumed in kWh.

$$\begin{gathered} \therefore Theenergyconsumed(inaday)=0.82\left(kW\right)x6\left(hr\right) \\ =4.92kWh \\ letussupposethat30daysareinonemonth \\ \therefore Thetotalenegyconsumed(inamonth)=4.92x30 \\ =147.60kWh \\ =147.60electricalunits...(\because 1unit=1kWh) \end{gathered}$$

Step 4: Finding the cost of units in a month.

$$\begin{gathered} \because 1electricalunit\text{'}s\cos tisequalstoRs2. \\ \therefore 147.60electricalunit\text{'}s\cos twouldbe147.60x2 \\ =Rs295.20 \end{gathered}$$

Hence, the consumption of electric units in a house in a month is $147.60kWh$ and the cost of electricity consumed in a month is $Rs295.20$.