EXPERIMENT (1)

A) Brightness of bulbs in a series circuit

Aim 
To compare the brightness of bulbs in a series circuit

Problem
Is the brightness of bulbs in a series circuit affected by its number?

• What to change: The number of bulbs
• What to observe: The brightness of the bulb
• What to keep the same: The type and number of dry cells, and The type of bulb

Steps

1.  Two similar bulbs, dry cells and switches are used.
2. The following series circuit are set up.
    (a) One bulb connected in series with the switch and the dry cell.
    (b) Two bulbs connected in series with one another and with the switch and the dry cell.
3. The switches in both circuits are closed and the brightness of the bulbs is observed.

Observation

Number of bulbs in series	1	2
Brightness of bulb	Brighter	Dimmer

 Conclusion
When the number of bulbs used in a series circuit increases, the brightness of each bulb decreases.