Settling velocity increases with A. Specific gravity of solid particles B. Size of particles C. Depth of tank D. Temperature of liquid

The correct answer is B. Size of particles.

The settling velocity of a particle is the velocity at which it will settle in a fluid under the influence of gravity. The settling velocity is proportional to the square of the particle diameter and inversely proportional to the density of the fluid.

The specific gravity of the solid particles is not a factor in the settling velocity. The depth of the tank is also not a factor, as the settling velocity is independent of the distance from the surface of the fluid. The temperature of the liquid can affect the settling velocity, but only to a small extent.

Here is a more detailed explanation of each option:

• Option A: Specific gravity of solid particles. The specific gravity of a substance is its density relative to the density of water. The density of a particle is not a factor in its settling velocity.
• Option B: Size of particles. The settling velocity of a particle is proportional to the square of the particle diameter. This means that a particle that is twice as large as another particle will have four times the settling velocity.
• Option C: Depth of tank. The settling velocity of a particle is independent of the distance from the surface of the fluid. This is because the settling velocity is determined by the force of gravity, which is the same at all points in the fluid.
• Option D: Temperature of liquid. The temperature of the liquid can affect the settling velocity, but only to a small extent. This is because the viscosity of the liquid is affected by temperature. A more viscous liquid will have a lower settling velocity.