Testing electric circuits worksheet - Free Printable

Let's go through each circuit in the worksheet and determine whether the bulb(s) will light. We need to check if there is a complete path for current to flow from the battery (or power source), through the bulb, and back to the battery.

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Circuit 1:

- Diagram: Battery connected to a bulb in a simple loop.
- Analysis: Complete circuit with one battery and one bulb.
- ✔ Yes – The bulb will light.

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Circuit 2:

- Diagram: Two batteries and two bulbs in series.
- Analysis: Series circuit with two batteries and two bulbs. Current flows through both bulbs.
- ✔ Yes – Bulbs will light (though possibly dimmer due to higher resistance).

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Circuit 3:

- Diagram: A bulb with no battery.
- Analysis: No power source → no voltage → no current.
- ✘ No – The bulb will not light.

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Circuit 4:

- Diagram: Switch open, battery and bulb in circuit.
- Analysis: Open switch breaks the circuit.
- ✘ No – Bulb won't light (circuit is open).

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Circuit 5:

- Diagram: Three batteries in series, one bulb.
- Analysis: Multiple batteries provide higher voltage, but still a complete circuit.
- ✔ Yes – Bulb will light (possibly brighter).

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Circuit 6:

- Diagram: Two batteries in series, but no bulb? Wait — actually, it shows two batteries and a wire between them.
- Wait! There’s no bulb in this circuit.
- ✘ No – No bulb → no light.

> Correction: Looking closely, the diagram shows two batteries connected in series with no load (bulb). But even so, if there’s no bulb, no light. Also, the wire connects the batteries directly → short circuit, but no bulb means no lighting.

So: ✘ No

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Circuit 7:

- Diagram: Battery, switch (open), bulb.
- Analysis: Switch is open → circuit broken.
- ✘ No – Bulb does not light.

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Circuit 8:

- Diagram: Two batteries and a bulb, but the wires are disconnected at the top.
- Analysis: Open circuit — gap in the wire.
- ✘ No – No current flow.

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Circuit 9:

- Diagram: Two bulbs in parallel, but no battery.
- Analysis: No power source.
- ✘ No – Bulbs won’t light.

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Circuit 10:

- Diagram: One battery, one bulb, and another bulb in series.
- Analysis: All components in series, complete circuit.
- ✔ Yes – Both bulbs will light.

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Circuit 11:

- Diagram: Battery, bulb, and an open switch.
- Analysis: Switch is open → break in circuit.
- ✘ No – Bulb won’t light.

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Circuit 12:

- Diagram: Only a bulb, no battery or power source.
- Analysis: No power source.
- ✘ No – Bulb won’t light.

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Final Answers:

| Circuit | Will Bulb Light? |
|--------|------------------|
| 1 | ✔ Yes |
| 2 | ✔ Yes |
| 3 | ✘ No |
| 4 | ✘ No |
| 5 | ✔ Yes |
| 6 | ✘ No |
| 7 | ✘ No |
| 8 | ✘ No |
| 9 | ✘ No |
| 10 | ✔ Yes |
| 11 | ✘ No |
| 12 | ✘ No |

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Summary of Correct Responses:

- Yes: Circuits 1, 2, 5, 10
- No: Circuits 3, 4, 6, 7, 8, 9, 11, 12

✔ Answer Key:
1. Yes
2. Yes
3. No
4. No
5. Yes
6. No
7. No
8. No
9. No
10. Yes
11. No
12. No

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Explanation Tips:

- A bulb lights only if:
- There is a battery (power source).
- The circuit is complete (closed loop).
- There is no break (like open switch or gap).
- Even if multiple batteries are used, as long as the circuit is closed and includes a bulb, it will work.
- If there’s no battery, no light.
- If the switch is open, no light.
- If there’s a gap in the wire, no light.

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