Target Exam

CUET

Subject

Physics

Chapter

Current Electricity

Question:

A 16Ω wire is bent to form a square loop. A cell of 9 V is connected across one of its sides. The potential difference between the diagonals of the square loop is:

Options:

6 V

4.5 V

8 V

9 V

Correct Answer:

6 V

Explanation:

The correct answer is Option (1) → 6 V

Total resistance is 16 $\Omega$, so each side is 4 $\Omega$.

A 9 V battery is connected across side AB.

Let $V_A = 0\text{ V}$ and $V_B = 9\text{ V}$.

The current ($I$) through the series path $B \to C \to D \to A$ is:

$I = \frac{V}{R_{total}} = \frac{9\text{ V}}{4\Omega + 4\Omega + 4\Omega} = \mathbf{0.75\text{ A}}$
 

Calculating the voltage drop ($I \times R$) of 3 V across each side:

  • $V_B = 9\text{ V}$

  • $V_C = 9\text{ V} - 3\text{ V} = \mathbf{6\text{ V}}$

  • $V_D = 6\text{ V} - 3\text{ V} = \mathbf{3\text{ V}}$

  • $V_A = 0\text{ V}$

The question is interpreted as asking for the potential difference across either diagonal of the square, i.e., between the opposite vertices (such as A and C):

$\Delta V = V_C - V_A = 6\text{ V} - 0\text{ V} = \mathbf{6\text{ V}}$
 
Note: The given answer is as per NTA.