1.) The average resistivity of the human body (apart from surface resistance of

Question

1.)           The average resistivity of the human body (apart from surface resistance of the skin) is about 5.0 ohm*m . The conducting path between the right and left hands can be approximated as a cylinder 1.6 m long and 0.10 m in diameter. The skin resistance can be made negligible by soaking the hands in salt water.

A.

    What is the resistance between the hands if the skin resistance is negligible?

   B.

If skin resistance is negligible, what potential difference between the hands is needed for a lethal shock current of 100 { m mA}? (Your result shows that even small potential differences can produce dangerous currents when the skin is damp.)

Explanation / Answer

A. Resistance between the hands=resistivity*Length of hand/area of hand

                                                                =5*1.6/(pi*0.12/4)

                                                                =1018.6 ohm

B. Current, I=100*10-3 A

V=I*R=1018.6*100*10-3=10.19 V

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