Red Seal Electrician Practice
DC circuitsQuestion 775 of 1506

A 70 Ah battery is rated at 3.5 A. It is connected to a load that draws 70 A. Will it last exactly 1 hour?

  1. No, because the battery will last more than 1 hour
  2. No, it will run for 20 hours
  3. Yes, exactly 1 hour in all cases
  4. Probably not; it will probably run down in less than 1 hour
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Correct answer: Probably not; it will probably run down in less than 1 hour

At high current, heat in the internal resistance changes the chemical reactions, so the simple formula is only an approximation.

Source: Lessons in Electric Circuits I: DC (Kuphaldt), 11.3: Battery Ratings

Practice dc circuits

Questions last reviewed: 18 October 2026