AIIMS 2018 Physics Surface Tension MCQ Question

When a needle of length $l$ m and mass $m$ kg is placed horizontally on the surface of water (H₂O), it experiences an upward force due to surface tension $T$. The total upward force from the surface tension acting along the length of the needle is $2Tl$ (since surface tension acts along both sides), which must balance the weight of the needle $mg$ for it to float. Therefore, setting these forces equal gives us the equation $2Tl = mg$, leading to $T = \frac{mg}{2l}$. The other options are not applicable as they do not provide relevant or correct expressions for surface tension in this context.