AIIMS 2019 Physics Spring Force MCQ Question

To determine the maximum extension in the spring, we can apply the principle of conservation of energy. When the blocks are released, the potential energy stored in the spring at maximum extension (U = 1/2 kx²) equals the gravitational potential energy lost by the blocks (mgh). Given the spring constant $k = 20 \, \text{N/m}$, the maximum extension $x$ can be calculated, leading to $x = \frac{20}{3} \, \text{cm}$. Other options do not satisfy the energy conservation equation or result from incorrect calculations of potential energy.