Circuit testing worksheet asking whether bulbs will light in various circuit diagrams.

Let's analyze each circuit in the worksheet to determine whether the bulb(s) will light. For a bulb to light, there must be a complete circuit with a power source (battery) and a closed path for current to flow.

We'll go row by row, left to right:

---

Row 1

Circuit 1 (Top-left):
- Battery + bulb in a closed loop.
- ✔ Complete circuit.
- Answer: Yes

Circuit 2 (Top-right):
- Two batteries and two bulbs in series.
- But the batteries are connected opposite (one positive to positive?).
- Actually, the symbols show both batteries oriented the same way — but if they're in series and connected correctly, it should work.
- Wait: Looking closely — the second battery is drawn with the positive terminal facing the negative of the first, so it’s correct.
- So two batteries in series → more voltage, two bulbs in series → current flows.
- ✔ Complete circuit.
- Answer: Yes

---

Row 2

Circuit 3 (Middle-left):
- Only a bulb, no battery.
- ✘ No power source → no current.
- Answer: No

Circuit 4 (Middle-right):
- Battery, bulb, and switch — but the switch is open (shown as an open gap).
- ✘ Open circuit → no current.
- Answer: No

---

Row 3

Circuit 5 (Left):
- Three batteries in series, one bulb.
- All connected in a loop.
- ✔ Complete circuit.
- Answer: Yes

Circuit 6 (Right):
- Two batteries connected in parallel? But they’re both connected directly to each other with no load.
- Wait: The wires connect both ends of the batteries together — this creates a short circuit across the batteries.
- But there’s no bulb in the circuit.
- ✘ No bulb, and shorted batteries — but the question is “Will the bulbs light?” There is no bulb here.
- So even though current flows, there's no bulb to light.
- Answer: No

---

Row 4

Circuit 7 (Left):
- Battery, switch, bulb — switch is open.
- ✘ Open circuit → no current.
- Answer: No

Circuit 8 (Right):
- Two batteries and one bulb.
- Batteries are in series? Or opposite?
- Looking at orientation: both batteries have their positive terminals pointing toward the bulb, so they are connected in opposition.
- One battery pushes current clockwise, the other counterclockwise — they cancel out.
- This is a balanced opposing circuit → net voltage = 0.
- ✘ No net EMF → no current.
- Answer: No

---

Row 5

Circuit 9 (Left):
- Two bulbs in parallel, but no battery.
- ✘ No power source.
- Answer: No

Circuit 10 (Right):
- One battery, three bulbs in series.
- All connected in a loop.
- ✔ Complete circuit.
- Answer: Yes

---

Row 6

Circuit 11 (Left):
- Battery, bulb, and switch open.
- ✘ Open circuit.
- Answer: No

Circuit 12 (Right):
- Only a bulb, no battery, no power source.
- ✘ No power → no light.
- Answer: No

---

✔ Final Answers:

| Circuit | Answer |
|--------|--------|
| 1 | Yes |
| 2 | Yes |
| 3 | No |
| 4 | No |
| 5 | Yes |
| 6 | No |
| 7 | No |
| 8 | No |
| 9 | No |
| 10 | Yes |
| 11 | No |
| 12 | No |

---

Summary:

- A bulb lights only if:
- There is a battery (power source),
- The circuit is closed (no open switches),
- There is a complete path from battery to bulb and back,
- And the components are properly connected (not opposing or missing).

Let me know if you'd like a visual explanation!