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7th Class Science Electric Current and Its Effects Question Bank Electric Current and Its Effects

  • question_answer
    A house-owner replaces a failed fuse for the lights of the house. When the lights are switched on, the second fuse also fails. The house-owner then uses a third fuse with a higher rating than the previous two. Why is this not a sensible thing to do?

    A) Fuses only allow the circuit to work if the rating is exactly right.

    B) The third fuse will melt because the rating is too high.

    C) Using a fuse with too high rating cause?s electric shocks.

    D) The circuit may work, but the fault is not corrected.

    Correct Answer: D

    Solution :

    The first two fuses melt, indicating that the current in the circuit is larger than expected. This is usually due to a fault in the electrical circuit (possibly having the live wire touching the metal casing). If a third fuse with a higher rating is used, the circuit will work, but the fault is not corrected. As the current is still larger than expected, this could result in overheating of the wires.


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