Question

Why is the resistance less when resistors are joined in parallel?

Answer 1

When resistances are connected in parallel the current in the circuit gets parallel branches to go from one point to another across which the potential difference is applied. The equivalent resistance is the reciprocal of the sum of the reciprocals of individual resistances.

Suppose there are two resistances r1 and r2,

Then the equivalent resistance is given by,

1/r = 1/r1 + 1/r2

So, the equivalent resistance is less when resistors are connected in parallel.