29Ω

Given,

The emf of the cell, E=6V

The value of internal resistance, r= 1 Ω

The volt meter reading across the setup, V=5.8V

The value of external resistance= R Ω

Formula used:

Figure shows the overview of the setup.

The voltage across the cell will be equal to that across the external resistance. So,

Solution:

The current flowing through the internal and external resistance are the same.

By substituting the given values in the eqn.1, we get i as

Or,

Or,

This current also circulate through the external resistance R. Hence from the eqn.1, we can write its expression as,

By substituting the values of ‘i’ and V, we get

Or,

Hence the resistance of the external resistor is 29Ω.