Most AEDs are set up to adjust the voltage based on the impedance, which is the:

Most AEDs are set up to adjust the voltage based on the impedance, which is the:

• A. distance between the two AED pads on the chest.
• B. actual amount of energy that the AED will deliver.
• C. resistance of the body to the flow of electricity.
• D. direction that the electrical flow takes in the body.

Answer: (C)

AEDs adjust the shock voltage by measuring the body's impedance, which is the body's resistance to the flow of electric current. This resistance varies with pad contact quality, skin moisture, chest thickness, and pad placement, so the device uses it to estimate how much current will actually pass through the heart. According to Ohm’s law, delivering the same current with higher resistance requires higher voltage, while lower resistance needs less voltage. That relationship is why impedance guides the voltage setting rather than relying on a fixed energy amount. The other ideas—pad distance, the energy delivered, or the direction of current—don’t define impedance in this defibrillation context.

AEDs adjust the shock voltage by measuring the body's impedance, which is the body's resistance to the flow of electric current. This resistance varies with pad contact quality, skin moisture, chest thickness, and pad placement, so the device uses it to estimate how much current will actually pass through the heart. According to Ohm’s law, delivering the same current with higher resistance requires higher voltage, while lower resistance needs less voltage. That relationship is why impedance guides the voltage setting rather than relying on a fixed energy amount. The other ideas—pad distance, the energy delivered, or the direction of current—don’t define impedance in this defibrillation context.