Correct Option
The working principle of a washing machine, particularly during its spin-dry cycle, is centrifugation. Centrifugation is a process that uses centrifugal force to separate components of a mixture based on their density. In a washing machine, the wet clothes and water are spun at high speeds. The centrifugal force pushes the denser clothes outwards against the drum walls, while the less dense water is forced through the perforations in the drum, thereby separating the water from the fabric. This is a mechanical separation technique.
Incorrect Options
Dialysis:
Dialysis is a process of separating molecules in a fluid by their differential diffusion through a semi-permeable membrane. It is primarily used in medical applications, such as kidney dialysis, to remove waste products from blood.
Reverse Osmosis:
Reverse osmosis is a water purification process that uses a partially permeable membrane to remove ions, unwanted molecules, and larger particles from drinking water. It involves applying pressure to force water molecules through the membrane, leaving contaminants behind. It is not related to the mechanical separation of water from clothes.
Diffusion:
Diffusion is the net movement of particles from an area of higher concentration to an area of lower concentration. It is a passive transport process that occurs due to the random motion of particles and does not involve mechanical force or spinning for separation in the context of a washing machine.