Question

If the resistance of your body is $100000\,\Omega $ what would be the current that flows through your body when you touch the terminals of a $12\,V$battery?

Answer 1

Hint: The circuit becomes complete when the terminals of a battery are connected across an element, say a resistor and current starts flowing through it.
Considering the resistor to be an ohmic resistor when nothing is mentioned about the resistor, we apply the ohm’s law.
Ohm’s law states that for given physical conditions, the voltage drop across a particular element in a circuit is directly proportional to the current flowing through the element.
The mathematical expression is given as $V \propto I$
Replacing the proportionality sign we get $V = IR$ where R is the resistance of the element.

Complete step by step solution:
Consider your body to be the resistor of resistance $R = 100000\,\Omega $ .
Let’s visualize the situation.

When you touch the terminals of a $12\,V$ battery, the circuit gets complete and current flows through the body.
By ohm’s law,
$V = IR$ where $V = 12\,V,\,\,R = 100000\,\Omega $
Substituting in the equation,
$ \Rightarrow 12 = I \times 100000$
$ \Rightarrow I = \dfrac{{12}}{{100000}}$
$ \Rightarrow I = 0.00012\,A$
Hence $0.00012\,A$ flows through the body.

Note: Ohm’s law can be applied only in case of ohmic resistors. For non-ohmic resistors, we solve the circuit using conventional analysis. Take the resistor to be an ohmic resistor unless stated otherwise. The value of R changes with a change in physical conditions. Also, the value of R changes with the change in the geometry of the resistor.