Three resistors of 4,6 and 12 ohms respectively are connected in parallel. The equivalent resistance is ?

Option D

Reciprocal of Resistance in parallel combination is sum of individual resistance.

1/R = 1/r1 + 1/r2 + ... + 1/rn

Explanation:
The voltage across each resistor within a parallel combination is exactly the same but the currents flowing through them are not the same as this is determined by their resistance value and Ohm's Law. Then parallel circuits are current dividers.