Question

How many joules are there in one kilowatt hour?
$A.\;35 \times {10^6}\;J$
$B.\;3.5 \times {10^6}\;J$
$C.\;36 \times {10^6}\;J$
$D.\;3.6 \times {10^6}\;J$

Answer 1

Hint: - Energy is the property that transfers when a work is done from one body to another. Energy unit is very important.

Complete step-by-step solution -
Energy is a quantitative property which transfers whenever work is done from one body to another. And we may conclude the energy is the ability to do some sort of physical activity. This is a stored quantity, and the energy conservation law states that energy cannot be produced or destroyed but can be transferred from one form to another only. This can occur in various ways, including potential, kinetic, thermal, electrical, chemical, nuclear, or other.
Units of Energy
The Energy unit of SI is Joule.
The universal unit system which is SI unit of energy calculation is Joule named after James Prescott Joule.
Joule is a derived unit which represents the energy used to apply a force of 1 newton over a distance of 1 metre. Energy is often expressed in other units that are not part of the SI, such as ergs, calories, British thermal units, kilowatt-hours, and kilocalories, which allow a factor of conversion when expressed in SI.
The Energy Commercial Module is 1kWh.
1 kilowatt-hour is characterized as the amount of energy consumed by a device at a constant rate of one kilowatt in one working hour. The relation between commercial and SI is therefore given by:
$\Rightarrow 1kWh = 1kW \times 1h$
$\Rightarrow 1kWh = 1000W \times 1h$
$\Rightarrow 1kWh = 1000 \times \dfrac{J}{s}\times {3600}s$
$\Rightarrow 1kWh = 3.6 \times {10^6}J$

Hence option D is the correct answer and as per this in one kilowatt hour $3.6 \times {10^6}J$ are there.

Note: - In this question we saw that unit of energy and its conversion is very important for us to answer the question. Hence, we must remember the definition of energy and its formula and units in which they are expressed.