Question

How will you connect three resistances of 4 ohms to get $6\Omega$ ?

• A. all in series
• B. one series and two parallel
• C. all in parallel
• D. two series and one parallel.

Answer 1

The correct option is B one series and two parallel

To get an equivalent resistance of 6 ohms, we have to use both parallel and series connection in the circuit. First, the two resistors are connected in parallel to obtain a combined resistance of 2 ohms and then the combined resistance in connected in series with the third resistor to give a total resistance of 6 ohms.
That is, for the two resistors in parallel the resistance is given as $\frac{1}{4}+\frac{1}{4}=\frac{1}{0.5}=2ohms$ and this is added with the resistance of the third resistor in series as $2+4=6$ ohms.