Answer to Question #33298 in Electric Circuits for ravi shekhar azad

Question

why is the terminal voltage of the cell less than it's emf ?

Answer 1

All sources have a non-zero effective internal resistance, that's why all sources have voltage drop on internal resistance.
U = E - Ur, where
U is terminal voltage,
E is EMF,
Ur is voltage drop on internal resistance,
Ur=I*r, where r is internal resistance.