Which one of the following is the value of 1 kWh of energy converted into joules ?

The kilowatt-hour (kWh) is the commercial unit of electrical energy, representing the energy consumed when one kilowatt of power is used for one hour [2]. To convert this into joules, the SI unit of energy, we break down the components: 1 kilowatt equals 1,000 watts, and 1 hour equals 3,600 seconds. Since 1 watt is defined as 1 joule per second (1 J/s), the total energy in joules is calculated by multiplying power in watts by time in seconds: 1,000 W × 3,600 s = 3,600,000 J [2]. This value is expressed in scientific notation as 3.6 × 10^6 J [2]. Therefore, 1 kWh is equivalent to 3.6 million joules, which corresponds to the value 3.6 × 10^6 J provided in the options.

Sources

1. [1] Science , class X (NCERT 2025 ed.) > Chapter 11: Electricity > 11.8 ELECTRIC POWER > p. 191
2. [2] Science , class X (NCERT 2025 ed.) > Chapter 11: Electricity > What you have learnt > p. 192