Define power. Write the commercial unit and $SI$ unit of electrical energy. An electrical geyser of $1.5 \, kW$ works for $2$ hours. Find the electrical energy units consumed in a day.

(N/A) Power is defined as the rate of doing work or the rate of energy consumption.
The commercial unit of electrical energy is $kWh$ (kilowatt-hour), and the $SI$ unit is Joule $(J)$.
Given:
Power $(P)$ = $1.5 \, kW$
Time $(t)$ = $2 \, \text{hours}$
Electrical energy consumed $(E)$ = $P \times t$
$E = 1.5 \, kW \times 2 \, \text{h} = 3 \, kWh$.
Therefore, the electrical energy consumed in a day is $3 \, \text{units}$ (since $1 \, kWh = 1 \, \text{unit}$).