Battery Life: Given a battery of 9 volts, an internal resistance of 1 ohm, and a rating of 1.2 ampere-hours, how long will the battery last if connected to a load resistance of 8 ohms?

Answer: Look at the circuit below. The total resistance of the series circuit is 9 ohms; therefore, the load current is 1 ampere. The equation for battery life says that it equals the rating divided by the load current. A rating of 1.2 amp-hours divided by a load current of 1 ampere gives a life of 1.2 hours.

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