Question

In the given circuit, the terminal potential difference of the cell is :

• A. 2 V
• B. 4 V
• C. 1.5 V
• D. 3 V

Answer 1

Answer: (A)

2 V

Answer 2

The circuit has a 3 V cell connected to resistances of $1 \, \Omega$, $4 \, \Omega$, and $4 \, \Omega$. The total resistance $R_{\text{total}}$ of the circuit is calculated as:
$R_{\text{total}} = R_{\text{internal}} + R_{\text{external}}$
The external resistance is a parallel combination of $4 \, \Omega$ and $4 \, \Omega$:
$R_{\text{parallel}} = \frac{1}{4} + \frac{1}{4} = 2 \, \Omega.$
Thus, the total resistance becomes:
$R_{\text{total}} = 1 \, \Omega + 2 \, \Omega = 3 \, \Omega.$
The current in the circuit is:
$i = \frac{\text{EMF}}{R_{\text{total}}} = \frac{3 \, \text{V}}{3 \, \Omega} = 1 \, \text{A}.$
The terminal potential difference $V_{\text{terminal}}$ is given by:
$V_{\text{terminal}} = \text{EMF} - i R_{\text{internal}} = 3 \, \text{V} - (1 \, \text{A} \cdot 1 \, \Omega) = 2 \, \text{V}.$
Final Answer: 2 V