1 kWh (kilowatt-hour) is equal to 3,600,000 joules (3.6 × 10⁶ J or 3.6 MJ). The kilowatt-hour is the commercial unit of electrical energy. It represents the energy consumed when a device with a power of 1 kilowatt operates continuously for 1 hour.
1 kWh = 3,600,000 joules (3.6 × 10⁶ J).
1 kWh = 3.6 MJ (megajoules).
kWh is the commercial unit of electrical energy used for electricity billing.
1 kWh = 1000 Wh (watt-hours).
Derivation: 1 kW × 1 hour = 1000 W × 3600 s = 3,600,000 J.
1 unit of electricity on a bill equals 1 kWh.
Energy formula: E (kWh) = Power (kW) × Time (h).
Step-by-step derivation:
1 kWh = 1 kilowatt × 1 hour = 1000 watts × 3600 seconds = 1000 J/s × 3600 s = 3,600,000 J = 3.6 × 10⁶ J = 3.6 MJ
Key relations used:
| Unit | Equivalent |
|---|---|
| Joules (J) | 3,600,000 J |
| Megajoules (MJ) | 3.6 MJ |
| Calories (cal) | 860,421 cal |
| BTU | 3412.14 BTU |
| Watt-hours (Wh) | 1000 Wh |
Note: 1 unit of electricity on your electricity bill = 1 kWh
How to calculate energy consumption:
Formula: Energy (kWh) = Power (kW) × Time (hours)
Examples:
Electricity bills charge per kWh (called a 'unit'), making kWh the most important practical unit of energy.
1 kWh (kilowatt-hour) is equal to 3,600,000 joules (3.6 × 10⁶ J or 3.6 MJ). This is derived as: 1 kW × 1 h = 1000 J/s × 3600 s = 3,600,000 J.
A kilowatt-hour (kWh) is the commercial unit of electrical energy. It is the energy consumed when an electrical device of power 1 kilowatt (1000 watts) operates continuously for 1 hour. It equals 3.6 × 10⁶ joules.
1 kWh = 1 kilowatt × 1 hour = 1000 W × 3600 s = 1000 J/s × 3600 s = 3,600,000 J = 3.6 MJ.
kW (kilowatt) is a unit of power — it measures the rate of energy consumption. kWh (kilowatt-hour) is a unit of energy — it measures the total energy consumed. A 2 kW appliance running for 3 hours consumes 6 kWh of energy.
1 MJ (megajoule) = 1,000,000 J. Since 1 kWh = 3,600,000 J, we get: 1 MJ = 1/3.6 kWh ≈ 0.2778 kWh. Conversely, 1 kWh = 3.6 MJ.
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