Standard Science Primary 5 Systems

Look at the circuit diagram. What will happen when the switch is closed?

A The battery will recharge.
B The bulb will not light up because the current will bypass it.
C The bulb will light up very brightly.
D The switch will melt immediately.
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Worked Solution

Step 1: The switch is connected in a parallel branch directly across the bulb (a short circuit). Step 2: Electric current takes the path of least electrical resistance. Step 3: The wire with the closed switch has almost zero resistance compared to the bulb filament. Step 4: All current will bypass the bulb, so it will not light up.

Correct answer: The bulb will not light up because the current will bypass it.

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