Question

The effective resistance of a circuit containing resistances in parallel is.

• A. equal to the sum of the individual resistances.
• B. smaller than any of the individual resistances.
• C. greater than any of the individual resistances.
• D. sometimes greater and sometimes smaller than the individual resistances.

Answer 1

The correct option is B smaller than any of the individual resistances.

The effective resistance of a circuit containing resistances in parallel is smaller than any of the individual resistances.

For example : $R_1=2\Omega$ and $R_2=3\Omega$

$\therefore$ Effective resistance $\frac{1}{R_p}=\frac{1}{R_1}+\frac{1}{R_2}$

OR $\frac{1}{R_p}=\frac{1}{2}+\frac{1}{3}$ $R_p=1.2\Omega <2\Omega$