HOTS Science Primary 5 Systems

Study the mixed circuit shown. If switch S1 is opened, what will happen to the bulbs?

A Both B1 and B2 will remain lit.
B Only B1 will go out.
C Only B2 will go out.
D Both B1 and B2 will go out.
Show Worked Solution

Worked Solution

Step 1: Identify the position of switch S1. It is located on the main series path connecting to the battery. Step 2: Identify the arrangement of B1 and B2. They are in parallel to each other, but draw current through the main path. Step 3: Opening S1 breaks the main circuit loop. Step 4: No electric current can flow from the battery to ANY branch, so both bulbs go out.

Correct answer: Both B1 and B2 will go out.

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