In a hydraulic system, force is transmitted by which medium?

• A. Fluid (liquid)
• B. Gas
• C. Solid
• D. Magnetic field

Answer: (A)

Force in a hydraulic system is transmitted through a fluid, specifically a liquid. This works because a confined liquid transmits applied pressure uniformly in all directions, and liquids are essentially incompressible under normal operating pressures. That means when you apply force on a small piston, the pressure rises and is felt by the entire fluid. The same pressure acts on the larger piston, producing a larger force since force equals pressure times area (F = P × A). This creates the hydraulic advantage that lets small input forces generate much larger output forces. Gases are compressible, so they don’t transmit steady pressure as effectively, solids don’t convey pressure in the same fluid-like way, and magnetic fields aren’t the mechanical medium here.