AIIMS 2019 Physics Hydraulic Lift MCQ Question

To find the maximum pressure that the smaller piston must bear, we use the formula for pressure, $P = \frac{F}{A}$, where $F$ is the force (weight of the car) and $A$ is the area of the piston. The weight of the car is calculated as $F = m \cdot g = 3000 \, \text{kg} \cdot 9.81 \, \text{m/s}^2 = 29430 \, \text{N}$. Converting the area from cm² to m² gives $A = 425 \, \text{cm}^2 = 0.0425 \, \text{m}^2$. Thus, the pressure is $P = \frac{29430 \, \text{N}}{0.0425 \, \text{m}^2} \approx 6.92 \times 10^5 \, \text{Pa}$, which corresponds to option B, not A.

Option A is incorrect because it miscalculates the pressure based on the given values. Options C and D are also incorrect as they do not match the calculated pressure.