AIIMS 2019 Physics Heating Effect of Current MCQ Question

When 20% of the heating coil is removed, the effective heating power of the kettle is reduced to 80% of its original capacity. Since it takes 12 minutes to boil 1 litre of water (H₂O) at full power, the time required to boil the same amount of water with reduced power can be calculated as follows: $\text{New Time} = \frac{12 \text{ minutes}}{0.8} = 15 \text{ minutes}$. However, this calculation is incorrect; the correct approach considers the inverse relationship between power and time, leading to $\text{New Time} = 12 \text{ minutes} \times 1.25 = 15 \text{ minutes}$. Therefore, the correct option is 9.6 minutes, which reflects the reduced efficiency of the kettle. Other options like 14.4, 16.8, and 18.2 minutes do not accurately represent the calculations based on the reduced heating power.