Write the expressions for the equivalent resistance R of three resistors R₁, R₂ and R₃ joined in (a) parallel, (b) series.

State how are the two resistors joined with a battery in each of the following cases when —

(a) same current flows in each resistor,

(b) potential difference is same across each resistor,

(c) equivalent resistance is less than either of the two resistances,

(d) equivalent resistance is more than either of the two resistances.

State two differences between the e.m.f. and terminal voltage of a cell.

Name two factors on which the internal resistance of a cell depends and state how does it depend on the factors stated by you.