Question

Electrical currents of as little as approximately 0.06 A can be dangerous, and even fatal. Currents of this magnitude can make the heart fibrillate (beat in an uncontrolled manner). The resistance of a human body can be as high as Omega100 kΩ for contact with dry skin; but the resistance can be a hundred times smaller for wet skin, or if the skin is broken. Calculate the voltages that can cause a current of 0.06 A through a human body for dry skin and for wet skin.

Answer 1

Step-by-step explanation:

From ohms law.

V=IR

Then, if the dry skin has a resistance of 100KΩ

R=100kΩ

1kΩ=1000Ω

R=100000Ω

Dry skin

The current of 0.06A

Then,

V=100000×0.06

V=6000Volts

That is a very big voltage

V=6KV

For a wet skin

The resistance of the body is , 100 times smaller than dry skin

Then,

R=100kΩ/100

R=1kΩ =1000Ω

The resistance of wet skin is 1000ohms

Using ohms law

V=IR

V=0.06×1000

V=60Volts

Therefore, a large voltage of 6000Volts can cause a current of 0.06A in a dry skin while, a voltage of 60V can cause a current of 0.06A in a wet skin

Answer 2

6000V and 60V respectively

Step-by-step explanation:

According to Ohm's law, the voltage (V) passing across a conducting material is related to the current (I) flowing through the material and the resistance R of the material as follows;

V = I x R ----------------------(i)

(a) From the question, let's calculate the voltage for dry skin as follows;

I = 0.06A

R = 100kΩ = 100 x 10³Ω

Substitute these values into equation(i) as follows;

V = 0.06 x 100 x 10³

V = 6000V

Therefore, the voltage that can cause a current of 0.06A through a human body for dry skin is 6000V

(b) From the question, let's calculate the voltage for wet skin as follows;

I = 0.06A

R = 100 times smaller than that of dry skin

ie. R = 100kΩ / 100 = 100 x 10³Ω / 100 = 1000Ω

Substitute these values into equation(i) as follows;

V = 0.06 x 1000

V = 60V

Therefore, the voltage that can cause a current of 0.06A through a human body for wet skin is 60V