Question

A human being can be electrocuted if a current as small as 50mA passes near the heart. An electrician working with sweaty hands makes good contact with the two conductors he is holding, one in each hand. If his resistance is $\mathbf{2000}\mathbf{\Omega }$, what might the fatal voltage be?

Short answer

The value of the fatal voltage is 100V.

Step-by-step solution

The given data

1. Current passing near the heart is, l = 50mA or 0.050 A
2. Resistance,$\mathrm{R}=2000\mathrm{\Omega }$

Understanding the concept of the Ohm’s Law

Ohm’s law states that the potential difference is directly proportional to the current and the constant of proportionality is called resistance.

We can find the fatal voltage by substituting the given values of the current and the resistance in the formula for Ohm’s law.

Formula:

The voltage equation from Ohm’s law, V = lR …(i)

Here, V is the potential difference, l is current, R and is resistance.

Calculation of the fatal voltage

Using the given data in equation (i), we can get the value of the fatal voltage as follows:

$$\begin{gathered} \mathrm{V}=(0.050\mathrm{A})\left(2000\mathrm{\Omega }\right) \\ =100\mathrm{V} \end{gathered}$$

Therefore, the fatal voltage is 100V.