Questions: Building a Simple Circuit

Question 1

You connect a battery to a light bulb with two wires, but the bulb does not light up. What should you check first?

• A. Replace the battery — it must be dead
• B. Check that all connections are tight and the circuit forms a complete loop
• C. Use thicker wires
• D. Try a bigger light bulb

Answer: (B)

Loose connections and incomplete loops are the most common reasons a circuit does not work. Before replacing any parts, check every connection point: is the wire firmly touching the battery terminal? Is the bulb screwed tightly into its holder? Is there an unbroken path from one battery terminal, through the bulb, and back to the other terminal?

Question 2

Electricity flows from the battery to the light bulb and stops there — it does not need to return to the battery.

• T. True
• F. False

Answer: False

Electricity must flow in a complete loop. Current flows out of one battery terminal, through the wire, through the light bulb (where electrical energy is converted to light and heat), through another wire, and back into the other battery terminal. If this loop is broken anywhere, no current flows and the bulb does not light.

Question 3

Your circuit has a battery and two light bulbs connected in a loop, but both bulbs are dim. Explain one possible reason.

Model answer: In a series circuit (one loop), the battery's energy is shared between the two bulbs, so each bulb gets less energy and glows dimmer than it would with only one bulb. Each bulb adds resistance to the circuit, reducing the current flowing through both.

This is a key hands-on discovery. Adding more bulbs in series makes each one dimmer because the same current flows through both, and each bulb uses some of the battery's voltage. This often surprises students who expect each bulb to glow at full brightness. It introduces the idea that energy is limited and must be distributed.