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    Question

    A metal plate with a circular hole at the centre is

    heated. What will happen to the area of the hole?
    A Increase Correct Answer Incorrect Answer
    B Decrease Correct Answer Incorrect Answer
    C Remain constant Correct Answer Incorrect Answer
    D Will increase first and then decrease Correct Answer Incorrect Answer

    Solution

    Assuming the disc is uniform and isotropic (the same in different directions), the hole will expand in the same ratio as the metal. It is because the thermal expansion equation applies to all lengths associated with the metal, including the circumference of the hole, since the edge of the hole is made out of metal. And if the circumference of the hole expands, so does the diameter.

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