Question

Find ‘i’ for the given loop.

A. $6/5A$
B. $8/9A$
C. $1/2A$
D. $1A$

Answer 1

We can use Kirchhoff’s current law to find the currents flowing around more complex circuits. We hopefully know by now that the algebraic sum of all the currents at a node (junction point) is equal to zero and with this idea in mind, it is a simple case of determining the currents entering a node and those leaving the node.

Complete step by step answer: A cell or battery is drawn with a long line and a shorter line. The long line is the positive side and the short line is the negative side.
Kirchhoff’s Current Law (KCL) is Kirchhoff’s first law that deals with the conservation of charge entering and leaving a junction.
Kirchhoff's Current Law or KCL, states that the “total current or charge entering a junction or node is exactly equal to the charge leaving the node as it has no other place to go except to leave, as no charge is lost within the node“.
We can use Kirchhoff’s current law to find the currents flowing around more complex circuits. We hopefully know by now that the algebraic sum of all the currents at a node (junction point) is equal to zero and with this idea in mind, it is a simple case of determining the currents entering a node and those leaving the node.
Applying Kirchoff's law starting from point A,
$5 - 5i - i - 3 + 6 - 3i = 0$
$\Rightarrow 8 - 9i = 0$
$\Rightarrow 9i = 8$
$\Rightarrow i = 8/9A$
Hence, option (B) is correct.

Note: Kirchhoff’s Current Law (KCL): “The algebraic sum of all currents entering and exiting a node must equal zero”