Question

Find the total current provided by the battery in the circuit as shown. Each resistor has a resistance of $1\Omega$

• A. 40A
• B. 20A
• C. 80A
• D. 10A

Answer 1

The correct option is A 40A

Have a detailed look at the part ABCOA of the circuit keeping in mind that all the resistors have same resistance.



Clearly, ABC and AOC have same potential drop across them.
Also, $\frac{R_{AB}}{R_{AO}}=\frac{R_{BC}}{R_{OC}}=1$
Therefore this part is in a balanced Wheatstone condition, which means that there will be no current through branch BO. So, AB and BC are in series combination with each other and AO and OC are also in series combination with each other. Also, ABC and AOC are in parallel to each other.
Now this is a very simple problem to solve right. Let's get started.
$R_{eq}$ (across AC) =$0.5\Omega$ (Don't just believe, find out for yourself)
Hence, $i=\frac{20}{0.5}=40A.$