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using Ohm\'s law ,(V=IR) estimate which of the following combinations of skin co

ID: 2078794 • Letter: U

Question

using Ohm's law ,(V=IR) estimate which of the following combinations of skin conditions and voltage sources (1a, 1b,....,4d/16 combinations total) would produce a shock strong enough to potentially stop the heart ( current > 100 mA)

1. dry hands ( resistance ~ 25k ohms) a. A 9-V energizer battery   

2. wet hands (resistance ~ 2.5 k ohms ) b. A 12 - V car battery

3. hands immersed in liquid ( 1000 ohms ) c. an 18 - V cordless drill battery

4. open wound in the skin ( 100 ohms ) A d. 110-V household outlet

Explanation / Answer

We know I=V/R

if I>100 mA then shock strong enough to potentially stop the heart

Combination 1: Hands immersed in liquid and 100V household outlet (3d) as I=(110/1000)=0.11 A=110 mA

Combination 2: Open wound skin in the skin and 12 V car battery (4b) as I=120mA

Combination 3: Open wound skin in the skin and 18V cordless drill battery (4c) as I=180mA

Combination 4: Open wound skin in the skin and 110V household outlet (4d) as I=1100mA