Transcript Slide 1

Option 1
Heat a fixed volume of water until the temperature has
increased by an amount of your choice.
Option 2
Heat a fixed volume of water for a time of your choosing.
In each case you must measure and record:
- the volume of water
- the current used by the bulb
- the voltage provided by the powerpack
- the temperature rise of the water
- the time taken
1. Calculate the power of the bulb
2. Calculate the energy used by the bulb
3. Calculate the heat energy that went into the water
4. Calculate the light energy produced by the bulb
5. Draw a Sankey diagram to show the energy change that took
place in the bulb
6. Calculate the efficiency
1. Calculate the power of the bulb
Use Power = Voltage × Current
2. Calculate the energy used by the bulb
Use Energy = Power × time
3. Calculate the heat energy that went into the water
Use Energy = mass × specific heat cap. × temp rise
4. Calculate the light energy produced by the bulb
Use light energy = total energy in – wasted heat energy
5. Draw a Sankey diagram to show the energy change that took
place in the bulb
Show the energy in and out using scaled arrows
6. Calculate the efficiency
Use the efficiency equation you learned last lesson