Brightness of lamp
1. Three pieces of insulated electric wires.
2. Three bulbs.
3. A battery (4.5 volt). 4. A strong pair of scissors or wire cutter.
1. Scrape the plastic at the ends of the three pieces of wire.
2. Connect a bulb to a battery, with one end of both wires attached to the battery terminal and the others to the two ends of the bulb- holder. Observe the brightness of the bulb.
3. Now connect two bulbs to the second battery, as shown in the picture.
What is the result?
The single bulb in the first case glowed much brighter than the two bulbs in the second case.
Why did this happen?
As against the first case, where there was just one bulb in the second case the electric current that passed through the circuit was being shared by the two bulbs. Therefore, since the energy given out by the battery was being shared in the second case, the brightness with which the bulbs glowed was lessened.