Electromotive Force (e.m.f) and Internal Resistance

 
3.3  Electromotive Force (e.m.f) and Internal Resistance
 
  Electromotive force, \(\varepsilon\)  
 

Energy transferred or work done by an electrical source to move one coulomb of charge in a complete circuit.

\(\varepsilon=\dfrac{E}{Q}\), where, \(\varepsilon\) = electromotive force, E = energy transferred / work done, Q = the amount of charge flowing

 
     
 
 
  Internal resistance, r  
 

Resistance caused by electrolyte in the dry cell.

\(\varepsilon > V\)

\(Ir = \varepsilon - V\)

 
     
 
  Formula relating E, V, I, R and r  
 
  • \(\varepsilon = V+Ir\)
  • \(\varepsilon = I(R+r)\)
 
     
 
 

 

Electromotive Force (e.m.f) and Internal Resistance

 
3.3  Electromotive Force (e.m.f) and Internal Resistance
 
  Electromotive force, \(\varepsilon\)  
 

Energy transferred or work done by an electrical source to move one coulomb of charge in a complete circuit.

\(\varepsilon=\dfrac{E}{Q}\), where, \(\varepsilon\) = electromotive force, E = energy transferred / work done, Q = the amount of charge flowing

 
     
 
 
  Internal resistance, r  
 

Resistance caused by electrolyte in the dry cell.

\(\varepsilon > V\)

\(Ir = \varepsilon - V\)

 
     
 
  Formula relating E, V, I, R and r  
 
  • \(\varepsilon = V+Ir\)
  • \(\varepsilon = I(R+r)\)