Question

Two currents 0.5 mA and 5 mA flow towards the junction in a circuit and three currents 1 mA, x and 2 mA flow away from the junction. The value of x (in mA) is

• A. 5.5
• B. 2.5
• C. 3
• D. 2

Answer 1

The Correct Option is B

Step 1: Apply Kirchhoff's Current Law (KCL).

Kirchhoff's Current Law states that the total current flowing into a junction must equal the total current flowing out of the junction. Mathematically:

\[ \text{Total current in} = \text{Total current out}. \]

Step 2: Identify the currents.

• Currents flowing towards the junction: \( 0.5 \, \text{mA} \) and \( 5 \, \text{mA} \).
• Currents flowing away from the junction: \( 1 \, \text{mA} \), \( x \, \text{mA} \), and \( 2 \, \text{mA} \).

Step 3: Set up the equation using KCL.

The total current flowing into the junction is:

\[ 0.5 + 5 = 5.5 \, \text{mA}. \]

The total current flowing out of the junction is:

\[ 1 + x + 2 = x + 3 \, \text{mA}. \]

Equating the total currents:

\[ 5.5 = x + 3. \]

Step 4: Solve for \( x \).

Rearrange the equation to isolate \( x \):

\[ x = 5.5 - 3 = 2.5 \, \text{mA}. \]

Final Answer: The value of \( x \) is \( \mathbf{2.5 \, \text{mA}} \), which corresponds to option \( \mathbf{(2)} \).