Question

The current through a certain heater wire is found to be fairly independent of its temperature. If the current through the heater wire is doubled, the amount of energy delivered by the heater in a given time interval will _________.a) increase by a factor of two.. b) decrease by a factor of two.. c) increase by a factor of four. d) decrease by a factor of four e) increase by a factor of eight

Answers

  2. Answer:

    Explanation:

    If the initial current is i,

    The energy delivered by the heater is given as

    Hi=i²Rt

    Then, when the current is double

    So the new current is 2i

    So the heat delivered will be

    Hn=(2i)²Rt

    Hn=4i²Rt

    Hn=4•i²Rt , i²Rt =Hi

    Hn=4•Hi

    Notice that the resistance of the heater doesn’t change.

    And the time will not change since we are considering the same time intervals (t)

    Conclusion, it is notice that the amount of heat delivered by the heater when the current was double, increase the heat delivered by a factor of 4.

    So the correct answer is C

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