The diagram in figure below shows a device which makes use of the principle of transmission of pressure.

(a) Name the parts labelled by the letters X and Y.

(b) Describe what happens to the valves A and B and to the quantity of water in the two cylinders when the lever arm is moved down.

(c) State one use of the above device.

(a) The parts are —

X → Press plunger

Y → Pump plunger

(b) When the lever arm is moved down, the valve B closes and the valve A opens, so water from cylinder P is forced into the cylinder Q.

(c) A hydraulic press is used for pressing cotton bales and goods like quilts, books, etc.