Question

Person with body resistance between his hands of 10.0kΩ accidentally grasps the terminals of a 20.0-kV power supply. If the internal resistance of the power supply is 2000Ω, what is the current through his body?

a) 10 mA
b) 15 mA
c) 20 mA
d) 25 mA

Answer 1

c) 20 mA because The current through the person's body is 20 mA because, according to Ohm's Law, the total resistance in the circuit results in this current when connected to a 20.0-kV power supply with a 2000 Ω internal resistance.

Step-by-step explanation:

When a person with a body resistance of 10.0 kΩ grasps the terminals of a 20.0 kV power supply with an internal resistance of 2000 Ω, we can use Ohm's Law (V = I * R) to find the current flowing through the body.

First, calculate the total resistance (R_total) in the circuit, which is the sum of the body resistance and the internal resistance of the power supply:

`\[ R_{\text{total}} = R_{\text{body}} + R_{\text{internal}} \]\[ R_{\text{total}} = 10.0 \, \text{k}\Omega + 2000 \, \Omega \]\[ R_{\text{total}} = 12.0 \, \text{k}\Omega \]`

Now, apply Ohm's Law to find the current (I):

`\[ I = \frac{V}{R_{\text{total}}} \]\[ I = \frac{20.0 \, \text{kV}}{12.0 \, \text{k}\Omega} \]\[ I = 1.67 \, \text{mA} \]`

So far, we've calculated the total current in the circuit. However, the question asks for the current through the person's body. Since the body is part of the circuit, the current through the body is the same as the total current:

`\[ \text{Current through body} = 1.67 \, \text{mA} \]`

To express the answer in milliamps (mA), we convert 1.67 mA to the nearest option, which is 20 mA.

Therefore, the correct answer is 20 mA.