Question

The four wires from a larger circuit intersect at junction A as shown. What is the magnitude and direction of the current between points A and B?

A. 2A from A to B
B. 2A from B to A
C. 3A from A to B
D. 2A from B to A

Answer 1

Hint: Kirchhoff's current law stipulates that the total current that passes into and out of a terminal or junction in an electric circuit must be equal. Kirchhoff's current law is thought to be a result of charge conservation.


Formula used:
All currents entering and exiting a node must have an algebraic sum of zero.
 \[\sum I = 0\]



Complete answer:
We have been provided in the question that,
The four wires from a larger circuit intersect at junction A as shown in the given circuit as below


According to Kirchhoff's junction rule, all currents flowing into and out of a branch point have an algebraic sum of zero, or
 \[\sum I = 0\].
Conventionally, current leaving a junction has a negative sign while current entering one has a positive sign.
Thus, \[4 + 5 - 6 = 3A\] at junction A. Since it is positive, current \[3A\] will flow from point A to point B.

Therefore, the correct option is C.


Note:For students doing these types of problems, it is necessary to master the electrical laws related with the circuits while studying them. Kirchhoff's law of electric circuits is widely regarded as the foundation of electric circuits and circuit analysis. Kirchhoff’s law can be used to calculate the values of electrical components such as resistors, inductors, and so on.