ANS:C - colloidal

Ultra centrifuges are primarily used for the separation of fine solid particles. Here's an explanation:

• Ultra Centrifuges: These are high-speed centrifuges capable of generating centrifugal forces several thousand times greater than the force of gravity. This high centrifugal force allows for the separation of particles based on their density and size.
• Fine Solid Particles: Ultra centrifuges are effective in separating fine particles, including colloidal particles and particles suspended in solutions, due to their ability to exert strong gravitational forces. They are particularly useful for separating particles with sizes in the micron range.
• Other Types of Separations:
  • Coarse Solid Particles: Generally, coarse particles settle out relatively easily and do not require the high centrifugal forces provided by ultra centrifuges.
  • Colloidal Particles: These are small particles suspended in a medium (such as a liquid or gas). Ultra centrifuges can effectively separate colloidal particles depending on their density and size.
  • Dissolved Particles: Ultra centrifuges are not typically used for separating dissolved substances, as dissolved particles are uniformly distributed at the molecular level within a solution and do not settle out under centrifugal force.