Question

The value 1Wh =
A. 36kJ
B. 3.6KJ
C. 3600KJ
D. 3.6MJ

Answer 1

Hint: In this question, we start with the definition of watt and watt-hour that is a watt is used to measure the power whereas watt-hour is used to measure the energy. Then we first write the formula for watt that is $1watt = 1\dfrac{J}{{\sec }}$ and after that we calculate for the watt-hour
That is $1Wh = 1\dfrac{J}{{\sec }} \times 3600\sec $.

Complete Step-by-Step solution:
We know that a watt-hour (Wh) is a unit of energy. Whereas, a watt is a unit of power, where power is the rate of energy dissipation or consumption. A watt-hour is a method to estimate the total value of work generated or performed. Home electrical devices work and that needs energy in electrical form. Services typically charge you for electrical energy with the kilowatt-hour (kWh) that is equal to 1,000 watt-hours.
Watt is the measure of rates of power consumption at a particular instant of time whereas, watt-hours measure the value of energy for a definite period.
From the above lines, we can conclude that
$watt = power = \dfrac{{energy}}{{time}} = \dfrac{J}{{\sec }}$
$1watt = 1\dfrac{J}{{\sec }}$
We also know that
$1Hr = 3600\sec $
So, we can write
$1Wh = 1\dfrac{J}{{\sec }} \times 3600\sec = 3600J$
Therefore $1Wh = 3600J$
Now converting joule to kilojoule we will get
$1Wh = 3600J = 3.6 \times {10^3}J$
$1Wh = 3.6KJ$
Hence option B is correct.

Note: For these types of questions, we need to know different units of energy and power. Then we need to know what are the units we used to calculate power in our daily life, for example Watt, Watt-hour, horsepower, etc.