Question

Three resistors, each of resistance $7.5\Omega$ are connected in parallel. Five resistors, each of resistance $8\Omega$ are connected in parallel. Another three resistors, each of resistance $6\Omega$ are in parallel. If these three parallel combinations are in series, find the effective resistance of the circuit.

• A. $3.1ohm$
• B. $5.1ohm$
• C. $6.1ohm$
• D. $7.1ohm$

Answer 1

The correct option is C $6.1ohm$

The arrangement is shoen.

For arrangement of $n$ resistors in parallel , the equivalent resistance is $\frac{R}{n}$.

Hence we get three resistances $\frac{7.5}{3}=2.5\Omega$ and $\frac{8}{5}=1.6\Omega$ and $\frac{6}{3}=2\Omega$ in series.

Hence finally equivalent resistance is $R=2.5+1.6+2=6.1\Omega$

Answer-(C)