Tag: work and power

Smallest commercial unit of energy is called Watt hour. It is defined as the amount of electric energy, which flows through a conductor in one hour, at a power of one watt.

$E = \dfrac{28.8 \times {10}^{3}}{3.6 \times {10}^{6}}$
   $= 8 \times {10}^{-3}  kwh$

The biggest commercial unit of energy is kilowatt hour $\left(kwh\right)$. It is also known as kilo-volt-ampere hour $\left(kVAh\right)$ and board of trade unit (BOT) or simply electric unit.

Commercial unit of electrical energy is  Kilowatt-hour  i.e  $kWh$ and 1 kWh is equal to 1 unit of energy.

As watt hour is the unit of energy, thus watt hour meter measures the amount of energy consumed for a given time period.

$1  kwh = 1  kw \times 1  h$
     $= 1000  w \times 1 \times 60 \times 60$
     $= 3.6 \times {10}^{6}  J$

Energy consumed by lamp in 2 hour     $E _l = 0.02\times 2 = 0.04$ kWh per day

$1$ kW  $ = 1000$ $\dfrac{J}{s}$            

We know  $1$ kWh $ = 3.6\times 10^6$ $J$

$1$ kW $ = 1000$ $\dfrac{J}{s}$