A2L Item 223
- Description: Identify the consequence of connecting a second bulb in parallel in a circuit.
- Goal: Hone understanding of parallel circuits.
- Source: 283-570 lights in parallel
- Keywords: Circuits, Electromagnetism, Power
The question for students:
A light bulb is connected to a battery as shown in Figure A below. When a second bulb is connected as shown in Figure B, what happens to the brightness of the original bulb?
- Increases
- Decreases
- Stays the same
- Bulb goes out
- Can’t determine
Commentary for teachers:
Answer
(3) If the battery cannot sustain the potential difference the bulb will dim somewhat. This can confuse students so any demonstration should not use a marginal battery.