The potential difference between the terminals of an electrical heating device is 40 V, when it draws a current of 2 A from the source. Which one of the following is the correct value of current drawn by the heating device if the potential is increased to 140 V?
- A.7 A
- B.5 A
- C.4 A
- D.2 A
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By Ohm's law the heater's resistance is 40 V divided by 2 A, which is 20 ohms, so at 140 V it draws 140 divided by 20, or 7 A. Ohm's law states that, at constant temperature, the current through a conductor is directly proportional to the potential difference across…
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