Answer :
To calculate the time it takes for a 3 kW immersion heater to raise the temperature of 5 kg of water from 30°C to 50°C, you can follow these steps:
1. Calculate the energy required to heat the water using the formula: Energy = mass * specific heat capacity * temperature change.
- Specific heat capacity of water is approximately 4200 J/kg°C.
- Temperature change = final temperature - initial temperature = 50°C - 30°C = 20°C.
2. Substitute the values into the formula: Energy = 5 kg * 4200 J/kg°C * 20°C.
3. Calculate the total energy required.
4. Convert the power of the immersion heater to watts: 3 kW = 3000 watts.
5. Use the formula: Energy = Power * time, where time is in seconds.
6. Rearrange the formula to solve for time: time = Energy / Power.
7. Substitute the calculated energy and power values to find the time in seconds.
8. Convert the time from seconds to minutes or hours for a more practical understanding of how long it will take for the immersion heater to heat the water.
By following these steps, you can determine the time needed for the 3 kW immersion heater to raise the temperature of 5 kg of water from 30°C to 50°C accurately.
