One megawatt is equivalent to
\[\begin{align}
  & A){{10}^{2}}W \\
 & B){{10}^{6}}W \\
 & C){{10}^{4}}W \\
 & D){{10}^{8}}W \\
\end{align}\]

Hint: Power is usually measured in watts. It is a measure of how much electrical energy is present in a circuit and how much electrical work can be done by that electrical circuit. Megawatts are used as a measure of the output of a power station.

Complete answer:
One megawatt is equal to \[{{10}^{6}}W\].
A megawatt is a unit for measuring the power that is equivalent to one million watts. One megawatt is equal to the energy produced by ten automobile engines. The unit Watt (W) is the yardstick for measuring power. For example, a hundred watt light bulb is rated to consume hundred watts of power when it is turned on. If such a light bulb were turned on for four hours it would consume a total of 400 watt-hours of energy. Therefore, Watts is a measure of instantaneous power, while watt hour is the measure of amount of energy consumed over a period of time. A megawatt (MW) is one million watts and kilowatt (kW) is thousand watts. Both terms are commonly used in describing the power generation or load consumption.

Therefore, answer is option B.

Note:
One watt is also equal to one joule per second. Some of the common power units include foot-pounds per minute, ergs per second (erg/s), , decibel milliwatts, kilocalories per hour or food calories per hour, BTU per hour (BTU/h),horsepower (hp) etc.
1 horsepower = 746 Watts
1W =30dBm (Decibel milliwatts)
1W = 3.421242 BTU/hr (British thermal unit)
1 Kilowatts = \[{{10}^{3}}\]W