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current in each strand? (b)What is the applied potential difference? (c) What is

ID: 1696434 • Letter: C

Question

current in each strand? (b)What is the applied potential difference? (c) What is the resistance of the cable? Swimming during a storm. Figure 26-29 shows a swimmer at distance D = 35.0 m from a lightning strike to the water, with current I = 78 kA. The water has resistivity 30 Ohm m, the width of the swimmer along a radial line from the strike is 0.70 m. and his resistance across that width is 4.00 kOhm. Assume that the current spreads through the water over a hemisphere centered on the strike point. What is the current through the swimmer? In Fig. 26-30, current is set up through a truncated right circular cone of resistivity 731 Ohm m, left radius a = 2.00

Explanation / Answer

Given
Distance between the lightning strike point and person D = 35 m
current = 78 KA
Resistivity of water = 30 -m

resistance of the person = 4 k

width of the person = 0.70 m

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Resistance of the water R = l/A

                                       = (30*35)/(3.14)*(35/2)^2

                                        = 1.09

Now the potential drop whenever the lightning reach the person

                                     V = IR

                                         = 78*10^3*1.09

                                          = 85 KV

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The current passing through the person

                                       I = V/R

                                        = 85 KV/4 k

                                        = 21.25 Amps