Tag: work and energy

We know that the electrical potential energy of electron $U=eV$ where e is the charge of electron and V be the voltage. So electron volt will be the unit of energy.  

Unit of energy is $ML^2T^{-2}$ 

1 horse power is equal to 746 watts.

1 watt is defined as 1 joule/second.

So $1kW = 1000W$, and $1 hour =60 \times 60 seconds $

So $1kWh = 3600kWs = 3,600,000Ws = 3,600,000J$

$1kWh=3.6*{{10}^{6}}J$

Watt is defined as joule per second. Kilowatt is $10^3$joule per second and kwh is kilowatt hour $10^3\times60\times60$ 

1 kWh is equal to 3.6 $\times$ 10$^{6}$

The kilowatt hour is a unit of energy equal to $3.6\times 10^6J$. If the energy is being transmitted or used at a constant rate (power) over a period of time, the total energy in kilowatt hours is the power in kilowatts multiplied by the time in hours. so if kWh is unit of energy so none of the option is correct hence option D is the answer.

A watt second (also watt-second, symbol W s or W. · s) is a derived unit of energy equivalent to the joule. The watt-second is the energy equivalent to the power of one watt sustained for one second.

calorie (cal) is the energy needed to increase 1 gram of water by 1°C at a pressure of 1 atmosphere.

 Electron volt (symbol eV) is a unit of energy equal to approximately 1.6×10⁻¹⁹  joules (symbol J). By definition, it is the amount of energy gained (or lost) by the charge of a single electron moving across an electric potential difference of one volt.