question_answer

A 3 \[\Omega \] resistor and 6\[\Omega \] resistor are connected in parallel and the combination is connected in series to a battery of 5 V and a 3\[\Omega \] resistor. What is the potential difference across the 6\[\Omega \] resistor?

A)  2 V                                        

B)  4 V

C)  3 V                                        

D)  1 V

Correct Answer: A

Solution :

                 As \[3\Omega \]AND \[6\Omega \]resistor are connected in parallel, so effective resistance is \[{{R}_{eff}}=\frac{6\times 3}{6+3}=2\Omega \] Again \[{{R}_{eff}}\]is connected in series with another resistor of \[3\Omega .\] Hence, total resistance in the current is \[=2\Omega +3\Omega =5\Omega \] Total current in the circuit \[=\frac{5}{5}=1\,A\] Potential difference across \[3\Omega \] is \[=1\times 3=3\,\text{vot}\] Now, potential difference across \[6\Omega \]resistor   \[=5-3=2V\]