AIIMS 2018 Physics Surface Tension MCQ Question

To lift the ring from the water surface, the force must overcome both the weight of the ring (mg) and the upward force due to surface tension acting along the perimeter of the ring. The total upward force from surface tension is given by 2TπR, as it acts on both the inner and outer edges of the ring. Therefore, the total force required is mg + 4TπR, which accounts for the weight of the ring and the contributions from surface tension, making option D the correct choice. Other options either miscalculate the contributions from surface tension or do not account for the full weight of the ring.