Resistance of a person's body

[Tcat]

Suppose that a person has a resistance of 13.0 kiloohms as part of a circuit which passes through his hands. This person accidentally grasps the terminals of a power supply with a potential difference of 16.0 V.
PART A:If the internal resistance of the power supply is 2100 ohms , what is the current through the person's body?
I calculated the current to be 1.06×10−3 A by using the equation I = V/(R_p + R_i)
PART B: To find the power dissipated in his body I thought you use the equation P = I*V so P =(1.06*10^-3 A)*(16.0V) which gave me 1.70*10^-2 which is wrong. What I am doing wrong??
Thank you for your help

 

[mcah5]

I think V isn't 16 V, since you want the voltage drop across his body, not the whole circuit

 

[quicknote]

in advance.I would like to clarify that the concept of "resistance of a person's body" is not a scientifically accurate term. Resistance is a property of a material or substance, not a person's body. However, we can use the concept of resistance to analyze the situation described.

To answer Part A, you correctly used Ohm's Law (I = V/R) to calculate the current through the person's body. However, the resistance of the person's body (R_p) should be included in the calculation as well. The correct equation would be I = V/(R_p + R_i), where R_i is the internal resistance of the power supply. Therefore, the current through the person's body would be 1.05 x 10^-3 A.

For Part B, the equation P = I*V is used to calculate the power dissipated in a resistive element, but in this case, the person's body is not the only resistive element in the circuit. The power supply also has an internal resistance (R_i) which should be taken into account. The correct equation for calculating the power dissipated in the person's body would be P = I^2 * R_p, where R_p is the resistance of the person's body. Plugging in the values, we get a power dissipation of 1.43 x 10^-6 W, which is a very small amount of power.

In conclusion, the main issue in your calculations was not taking into account the internal resistance of the power supply. It is important to consider all resistive elements in a circuit when calculating current and power. Additionally, as a scientist, I would advise against using terms like "resistance of a person's body" as it can be misleading and not scientifically accurate.