Standard Science Primary 5 Systems

Study the parallel circuit below. If switch S1 is opened while the other switch is closed, which bulb(s) will light up?

A Both L1 and L2
B Only L1
C Neither L1 nor L2
D Only L2
Show Worked Solution

Worked Solution

Step 1: The circuit is arranged in parallel, meaning there are independent pathways for the current. Step 2: Switch S1 controls only the top branch with bulb L1. Step 3: Opening S1 breaks the circuit for L1. Step 4: Current can still flow through the middle branch to L2, so only L2 lights up.

Correct answer: Only L2

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