Question

The current in the given circuit is

A. 0.3 amp
B. 0.4 amp
C. 0.1 amp
D. 0.2 amp

Answer 1

Hint: The given question is based on the concept of Kirchhoff’s voltage law. Using Kirchhoff’s voltage law formula we will solve this problem. As only one circuit is given, so only a single current flow is considered.

Formula used: \[V=IR\]
\[\sum{V}=0\]

Complete step by step answer:
The below equation represents the formula of Kirchhoff’s voltage law.
\[\sum{V}=0\]
Where the summation of voltages represents the number of voltage sources present in a circuit.
From the given circuit diagram, we have the data as follows.
The values of resistances = \[10\Omega ,20\Omega \]
The values of voltages = 2 V, 5 V
The formula that relates the current, voltage and the resistance is given as follows. This relation is defined by Ohm’s law.
\[V=IR\]
Where V is the voltage, I is the current and R is the resistance.
Let I be the current flowing through the circuit.
Now apply the KVL to the circuit given. So, we get,
\[10\times I-5+20I+2=0\]
The value of 5 V is taken to be negative, whereas, the value of the 20 V is taken to be positive, as we have considered the clockwise direction.
Now continue the further calculation.
\[\begin{align}
  & 10I+20I=5-2 \\
 & 30I=3 \\
\end{align}\]
Therefore, the value of the current is given as follows.
\[\begin{align}
  & I=\dfrac{3}{30} \\
 & I=0.1\,A \\
\end{align}\]
\[\therefore \] The value of the current through the circuit is 0.1 A.

So, the correct answer is “Option C”.

Note: This is a direct question. The formula used is the Ohm’s law formula. The units of the parameters should be known. In this question, the value of the current is asked, even, they can ask for either the value of resistance or the voltage by providing the values of the other two.