Question

A circuit contains two devices that are connected in parallel. If the resistance of one of these devices is 12 ohms and the resistance of the other device is 4 ohms, the total resistance of the two devices is
A. 0.333 ohms.
B. 16 ohms.
C. 3 ohms.
D. 0.0625 ohms

Answer 1

the answer is c. 3 ohms.

Answer 2

Answer: The correct option is 3 ohms.

Solution:

When resistors are connected in parallel the total resistance is given by :

$\frac{1}{R_{total}}=\sum_{i=1}^n\frac{1}{R_1}+\frac{1}{R_2}+...\frac{1}{R_n}$

$R_1=12 ohm$

$R_2=4 ohm$

$\frac{1}{R_{total}}=\frac{1}{12}+\frac{1}{4}=3 ohm$

The total resistance of the two devices is 3 ohm .