Questions

A group of emus is called as a mob. Emus is a kind of bird which is next to ostrich in its size.

Dust particles such as coal dust(smoke) are fine particle of a solid (carbon in the case of smoke) dispersed in air. They are colloidal systems and the particles are charged either positive or negative. In an applied electrical field, they are attracted towards the opposite electrodes. Movement of the particles towards the electrodes is known as 'electrophoresis'. Hence electrophoresis is applied to remove smoke within the chimeny itself without allowing it to escape into the air and cause nuisance.

Here Soda is a Heterogenous Mixture.

A Heterogeneous Mixture is a mixture having a non-uniform composition i.e, the mixture contains components in different phases. Using various means, the parts in the mixture can be separated from one another.