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Consider the resistor described in problem 1, carrying a current of 1.0 mA. If t

ID: 1444423 • Letter: C

Question

Consider the resistor described in problem 1, carrying a current of 1.0 mA. If the voltage drop across the resistor is 6.0 Volts, what is the resistance (in k ohm)? Electrical currents crossing the human body in excess of 0.3A are typically deadly. If electrical current has a direct pathway to the heart, it can interfere with your heart beat. In such a case, it only takes about 1 mA to be deadly. Fortunately, under dry conditions, the hand-to-hand resistance of the human body can be as large as 100,000 ohm. This is primarily due to the resistance of your skin. Unfortunately, if your skin is wet or chapped, your resistance can be as low as 1000 ohm. If you touch a 9 Volt transistor battery, placing one hand on the positive electrode, and the other hand on the negative electrode, what will be the current passing through your body with dry skin? With wet skin?

Explanation / Answer

Here,

3 (a)

voltage , V = 6 V

current , I = 1 mA

Using Ohm's law

R = V/I

R = 6/1 kOhm

R = 6 kOhm

the resistance is 6 kOhm

b)

Resistance , R = 1000 Ohm

V = 9 V

with dry skin

current = 9/(100 000)

current = 9 *10^-5 A

the current in the body is 9 *10^-5 A

with wet skin

current = 9/(1000)

current = 9 *10^-3 A

the current in the body is 9 *10^-3 A