Question

Five bulbs each rated

100 W

are used for

4 hours

, a heater rated

1500 W

is used for

2 hours

and an electric iron rated

1000 W

is used for

5 hours

. Calculate the total energy consumed by them in terms of commercial unit of energy. Convert the energy into joules.

Accepted Answer

Given that,

The power rating of one bulb is $100 W$ .

So, the power consumption of five bulbs will be $P_{1} = 100 \times 5 = 500 W = 0.5 kW$ ,

Time for which the five bulbs are used, $t_{1} = 4 hours$ ,

The power rating of a heater, $P_{2} = 1500 W = 1.5 kW$ ,

Time for which the heater is used, $t_{2} = 2 hours$ ,

The power rating of electric iron, $P_{3} = 1000 W = 1 kW$ ,

Time for which electric iron is used, $t_{3} = 5 hours$ ,

Let, $E$ be the total electric energy consumed.

We know that, $Electric energy consumed = Power rating \times Time of use$ ,

$\Rightarrow E = P_{1} \times t_{1} + P_{2} \times t_{2} + P_{3} \times t_{3}$

$\Rightarrow E = 0.5 \times 4 + 1.5 \times 2 + 1 \times 5 = 10 kWh$ .

Thus, the total energy consumed will be $E = 10 kWh$ . Where $kWh (kilowatt - hour)$ is the commercial unit of energy.

We know that, $1 kWh = 3.6 \times 10^{6} joules$ .

So, the total energy consumed in terms of $joules$ will be given by $E = 10 \times 3.6 \times 10^{6} = 3.6 \times 10^{7} joules$ .

Thus, the total energy consumed in terms of $joules$ is by $E = 3.6 \times 10^{7} joules$ .

Five bulbs each rated $100 W$ are used for $4 hours$ , a heater rated $1500 W$ is used for $2 hours$ and an electric iron rated $1000 W$ is used for $5 hours$ . Calculate the total energy consumed by them in terms of commercial unit of energy. Convert the energy into joules.

Important Questions on Sample Paper 4

Learn and Prepare for any exam you want !

Five bulbs each rated 100 W are used for 4 hours, a heater rated 1500 W is used for 2 hours and an electric iron rated 1000 W is used for 5 hours. Calculate the total energy consumed by them in terms of commercial unit of energy. Convert the energy into joules.

Important Questions on Sample Paper 4

Learn and Prepare for any exam you want !

Five bulbs each rated $100 W$ are used for $4 hours$ , a heater rated $1500 W$ is used for $2 hours$ and an electric iron rated $1000 W$ is used for $5 hours$ . Calculate the total energy consumed by them in terms of commercial unit of energy. Convert the energy into joules.