(a) How much voltage is required to cause possible heart fibrillation in a man,

Question

(a) How much voltage is required to cause possible heart fibrillation in a man, which corresponds to 450 mA of direct current?
V

(b) Why should rubber-soled shoes and rubber gloves be worn when working around electricity?

The human body can exhibit a wide range of resistances to current depending on the path of the current, contact area, and sweatiness of the skin. Suppose the resistance across the chest from the left hand to the right hand is 1.25 The human body can exhibit a wide range of resista 10^6?. (a) How much voltage is required to cause possible heart fibrillation in a man, which corresponds to 450 mA of direct current? V (b) Why should rubber-soled shoes and rubber gloves be worn when working around electricity?

Explanation / Answer

Voltage = I*R

i = 450 mA r = 1.25 *10^6

therefor v = 450 *10^(-3) *1.25*10^6

=5.625 * 10^(5) V

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2.To prevent getting "grounded" by forming an open circuit.

The earth is a reservoir of electrons. When the voltage in an electric wire becomes positive, what this really means is that an electrical vacuum has been established. Electrons will then want to flow into the positive wire. The human body has a resistance of about 10 megaohms, but very high positive voltages will cause electrons to flow up from the ground, through the body and into the source of positive voltage. The large amount of resistance generates a lot of energy in the form of heat, causing electrical burns. Rubber has enough resistance to block the flow of electrons even if the voltage is extremely high. Since electrons can't cross the rubber barrier between the boots and the ground, current can not flow. This establishes an open circuit.

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