Obtain an expression for the equivalent emf and internal resistance of two cells connected in parallel.

Derive the expression for equivalent emf and equivalent internal resistance of two cells connected in series.

Two cells, of e.m.f. 2E and E, and internal resistance 2 r and r respectivley are connected in parallel. Obtain the expression for the equivalent e.m.f and the internal resistance of the combination?

Obtain the expression for the equivalent resistance for 3 resistors connected in parallel and also write the expression of equivalent resistance for connection of' n' resistors.

Obtain an expression for equivalent resistance of two resistors connected in a series combination.