Kilojoules to Watt-hours conversion

How to convert kilojoules to watt-hours?

Sure! Kilojoules (kJ) and watt-hours (Wh) are both units of energy, but they are used in different contexts and are convertible between each other.

To convert kilojoules to watt-hours, you need to use the fact that 1 kilojoule is equal to 0.27778 watt-hours. This is because 1 kilojoule is equivalent to 1,000 joules, and 1 watt-hour (Wh) is equal to 3,600 joules.

The conversion factor can be derived as follows:

1 kilojoule (kJ) = 1,000 joules (J) 1 watt-hour (Wh) = 3,600 joules (J)

To convert kJ to Wh, use the following formula: $\text{Watt-hours (Wh)} = \text{Kilojoules (kJ)} \times \left(\frac{1 \text{ Wh}}{3,600 \text{ J}}\right) \times 1,000 \text{ J}$

Simplified: $\text{Watt-hours (Wh)} = \text{Kilojoules (kJ)} \times 0.27778$

For 1 kJ: $1 \text{ kJ} \times 0.27778 = 0.27778 \text{ Wh}$

So, 1 kilojoule is equal to 0.27778 watt-hours.

Real-World Examples

1. Food Energy

   • A medium-sized apple might contain about 200 kilojoules of energy. $200 \text{ kJ} \times 0.27778 = 55.56 \text{ Wh}$

2. Household Electricity

   • A typical LED light bulb might use around 15 kJ of energy per hour. $15 \text{ kJ} \times 0.27778 = 4.167 \text{ Wh}$

3. Daily Human Energy Expenditure

   • The average recommended daily energy intake for an adult might be around 8,700 kJ. $8,700 \text{ kJ} \times 0.27778 = 2,416.086 \text{ Wh}$ Or approximately 2.416 kWh (since 1 kWh = 1,000 Wh).

4. Battery Capacity

   • A typical AA battery might store about 14.5 kJ of energy. $14.5 \text{ kJ} \times 0.27778 = 4.028 \text{ Wh}$

5. Car Fuel Efficiency

   • 1 liter of gasoline contains about 34,200 kJ of energy. $34,200 \text{ kJ} \times 0.27778 = 9,500.76 \text{ Wh}$ Or approximately 9.501 kWh.

These examples show how kilojoules can be converted to watt-hours and illustrate the amount of energy in various real-world contexts.