Question

7
is a kwh a unit of power or a unit of work?
multiple choice
it is a unit of work since the time units cancel in ( w = pt ).
it is neither since it has both watts and hours.
it is a unit of power since a watt is a power unit.

Explanation:

Work \(W\) is calculated as \(W = Pt\) (where \(P\) is power and \(t\) is time). The unit \(kWh\) is \(1000\) watts \(\times\) \(1\) hour. Watts (\(W\)) is a unit of power and hour (\(h\)) is a unit of time. So \(kWh\) is a unit of work (energy). The first option correctly explains this using the formula \(W = Pt\). The second option is wrong as \(kWh\) is a valid unit of work. The third option is wrong because although watt is a power unit, when multiplied by time (hour), it becomes a work (energy) unit.

Answer:

It is a unit of work since the time units cancel in \(W = Pt\).