Q1: The settling velocity of a spherical particle of diameter less than 0.1 mm as per Stock's law, is

ANS:B -

Stocks's law describes the settling velocity of small spherical particles in a fluid medium. It states that the settling velocity (��Vs​) of a small spherical particle is directly proportional to the square of its diameter (�d). Mathematically, Stocks's law can be expressed as: ��=��2Vs​=kd2 Where:

• ��Vs​ = Settling velocity of the particle (m/s)
• �d = Diameter of the particle (m)
• �k = Proportionality constant

For particles with diameters less than 0.1 mm, Stocks's law may still be applicable, but the settling velocity would be relatively low due to the small size of the particles. The value of the proportionality constant (k) depends on various factors such as the density difference between the particle and the fluid, the viscosity of the fluid, and the shape of the particle. It is typically determined experimentally or calculated based on empirical correlations. Without the specific value of  k, it's challenging to provide an exact settling velocity for particles with a diameter less than 0.1 mm. However, it's important to note that the settling velocity would be relatively small compared to larger particles due to the influence of viscosity and other factors.