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1. The problem statement, all variables and given/known data

i)For a layer dry skin 1mm thick, determine the resistance of a 1 cm^2 area of skin.

Resistivity of dry skin : 3 x 10^4 ohms m

[3.0 x 10^5 ohms ]

ii)A person, who is well-earthed, accidentally grabs a wire of diameter 0.4 cm at a potential of 50V. His hand makes contact with the whole circumference of the wire over a distance of 9cm.

The average thickness of skin of his hand is 1mm. Estimate the current flowing through him.

[1.89 mA ]

2. Relevant equations

Resistance = resistivity(length)/area

V = IR

3. The attempt at a solution

For i) , I managed to solve it.

Using the equation directly.

For ii), I couldn't get the answer.

First, I calculate the surface area of the cylinder ( wire ) where it is in contact with the wire.

Surface area = pi . diameter . length

= pi . (0.4 x 10^-2) . (9 x 10^-2)

= 0.0011309 m^2

Then I multiply this surface area with the resistance of dry hand obtain in i)

Total resistance = surface area x resistance of dry skin 1 mm thick, area of 1m^2

= 0.0011309 x 3.0 x 10^5

Next, I used V = IR. Sub in total resistance and P.D of 50 V

The answer I got was 0.147 A. Totally off.

Thanks for the time !

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# Homework Help: Current Electricity - current flowing through hand

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