How is internal resistance of a cell related to temperature

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SUMMARY

The internal resistance of a cell is inversely related to temperature, as established by the Nernst Equation of electromotive force (Emf). As temperature increases, the Emf decreases, leading to a decrease in internal resistance (r). This is further supported by the observation that increased temperature enhances ion dissociation in solutions, resulting in higher conductance and lower resistance. However, it is crucial to note that both current (I) and terminal potential (V) vary with temperature, which complicates the direct application of the resistance formula r = (E - V) / I.

PREREQUISITES
  • Understanding of the Nernst Equation and its implications on Emf
  • Familiarity with the concepts of internal resistance and conductance in electrochemistry
  • Knowledge of how temperature affects ion dissociation in solutions
  • Basic proficiency in manipulating equations involving voltage, current, and resistance
NEXT STEPS
  • Study the Nernst Equation in detail to understand its impact on cell performance
  • Explore the relationship between temperature and ion mobility in electrolytic solutions
  • Investigate methods for measuring current and voltage in varying temperature conditions
  • Learn about the effects of temperature on electrochemical cell efficiency and performance
USEFUL FOR

Electrochemists, physics students, and engineers interested in battery technology and the effects of temperature on cell performance will benefit from this discussion.

Mr Virtual
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Relevant equations

int rest =emf - terminal potential / current
or
r=E-V/I

The attempt at a solution

Since Emf of a cell is inversely proportional to temp (From Nernst Equation of Emf of a cell), from the above equation, if temp is high, E is low, therefore r is low. So, acc. to me,
r decreases with increase in temp. But obviously, if E is decreasing, this must mean that r has increased. I am confused. Please help.

Edit: If we think in terms of solutions, then dissociation increases on heating, which means more ions available in cell, which means increase in conductance, which leads to the conclusion that resistance of the cell decreases with increase in temp.

Mr V
 
Last edited:
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I found out on the net that internal resistance decreases with increase in temperature.
 
Mr Virtual said:
Relevant equations

int rest =emf - terminal potential / current
or
r=E-V/I

it's r = (E-V)/I

and I and V do not remain constant if you change the temperature. I don;t think you can
use this formula to see what happens to R unless you measure I and V.
 

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