Which equation is correct for EMF: V-Ir or V=EMF-Ir?

[RoryP]

was just reading through my physics revision book when i noticed one of the equations for E.M.F
In class and the exams I am sure we used EMF= V-Ir, but the book said that V=EMF-Ir.
was just wondering which one was right so that i don't make a mistake in the future!
any help would be great!

 

[RoryP]

ignore that one guys, i just thought through it and it is V=EMF-Ir.
it has to be becuase the EMF is the maximum potential difference between 2 electrodes and the voltage is smaller than the EMF due to internal resistance!

 

[baba89]

Both equations are correct, as they represent different ways of expressing the same relationship between EMF, voltage, and current. The first equation, EMF = V-Ir, is known as Kirchhoff's voltage law, which states that the sum of the voltage drops in a closed loop must equal the EMF of the source. The second equation, V = EMF-Ir, is known as Ohm's law, which states that the voltage drop across a resistor is equal to the product of the current and the resistance. Both equations are frequently used in different contexts and can be interchanged depending on the specific problem being solved. It is important to understand the underlying principles behind each equation and use them appropriately in different situations.