1 kilo Watt-hour (kWh) is equals to ____.

The correct answer is option 4. $3.6 × 10^6$ joule.

\(1\) kilowatt-hour (\(1\) kWh) is a unit of energy commonly used in electricity billing, representing the energy consumed by a \(1\)-kilowatt (\(1\) kW) electrical appliance operating for one hour.

To convert kilowatt-hours to joules, we use the fact that \(1\) kilowatt-hour is equal to \(3.6 \times 10^6\) joules.

This conversion is derived from the definition of a watt-hour, where \(1\) watt-hour is equal to \(1\) watt (unit of power) multiplied by \(1\) hour (unit of time), which equals \(3.6 \times 10^3\) joules (since \(1\) watt \(= 1\) joule per second, and there are \(3600\) seconds in an hour).

Therefore, \(1\) kilowatt-hour (\(1\) kWh) equals \(1000\) watt-hours, which equals \(3.6 \times 10^6\) joules.

So, \(1\) kilowatt-hour (\(1\) kWh) is equivalent to \(3.6 \times 10^6\) joules.