Final answer:
A defibrillator does not cause serious burns thanks to the skin's good conductivity at high voltages and the use of a gel that aids in energy transfer, thereby preventing energy absorption by the skin and allowing it to reach the heart.
Step-by-step explanation:
Why Defibrillators Don't Cause Serious Burns
Considering the high-power output of a heart defibrillator, one might wonder why it doesn't produce serious burns. Despite the high voltage used in defibrillators, they are designed in such a way that the skin acts as a good conductor at high voltages. This means that instead of the energy being absorbed by the skin and causing burns, it lets the energy pass through more readily to the heart. To further aid in this, a specialized gel is used which helps in the efficient transfer of energy to the body. This gel essentially reduces the resistance of the skin, permitting the electrical current to pass through to the heart without heating the skin enough to cause burns.
If the skin had a 50 times larger resistance and the current remained the same, the power would increase significantly, leading to a much higher energy transfer to the skin, and thus, serious burns. However, the application of the conductive gel ensures that resistance is kept low and energy is not concentrated in one area, avoiding burn injuries while the device fulfills its life-saving function.