AIIMS 2019 Physics Ohm's Law MCQ Question

To find the current through the wire, we first determine its resistance $R$ using the formula $R = \frac{R}{l} \cdot l$. Given $\frac{R}{l} = \frac{1}{2} \, \Omega/\text{cm}$ and $l = 5 \, \text{cm}$, the resistance is $R = \frac{1}{2} \cdot 5 = 2.5 \, \Omega$. Applying Ohm's Law $V = IR$, where $V = 1 \, \text{V}$, we find the current $I = \frac{V}{R} = \frac{1}{2.5} = 0.4 \, \text{A} = 40 \, \text{mA}$ (or 40 Å).

Options B (4 Å), C (25 Å), and D (2.5 Å) are incorrect as they do not align with the calculated current based on the given resistance and applied voltage.