Current is allowed to flow in a metallic wire at a constant potential difference. When the wire becomes hot, cold water is poured on half portion of the wire. By doing so, its other portion becomes still more hot. Explain its reason.
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When cold water is poured on half portion of hot wire, it gets cooles there. Its temperature falls and hence its resistance decreases, due to it, the current in the wire increase. As heat produced, `H prop I^(2)`, therefore, the other portion of the wire becomes more hot.
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