Question

What is equivalent resistance? Derive the expression for effective resistance of two resistors connected in parallel.

Answer 1

Equivalent resistance is a different way of indicating 'total' resistance, which we calculate differently for series and parallel circuits.

Lets resistance $R_1,R_2,$ are connected in parallel resistance circuit. Then the equivalent resistance of the circuit is given by

$\frac{1}{R_{eq}}=\frac{1}{R_1}+\frac{1}{R_2}$