Questions

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.

A 40% solution of Formaldehyde known as Formalin is used in the preservation of biological specimens because of its hardening action on proteins. 

Fructose is an Organic molecule among the given options.

Organic Molecules :

An organic molecule is one which contains carbon, although not all compounds that contain carbon are organic molecules. Noticeable exceptions are carbon monoxide (CO), carbon dioxide (CO2), carbonates (e.g. calcium carbonate), carbides (e.g. calcium carbide) and cyanides (e.g. sodium cyanide). Pure carbon compounds such as diamond and graphite are also not organic compounds. Organic molecules can range in size from simple molecules to complex structures containing thousands of atoms.

Although carbon is present in all organic compounds, other elements such as hydrogen (H), oxygen(O), nitrogen (N), sulfur (S) and phosphorus (P) are also common in these molecules.

In simple, Molecules needed for life that have carbon are called Organic Molecules.

When the piece of iron is lowered into the water, the water level in the bucket increases. And so the pressure at the bottom of bucket also increases. Thus the total thrust at bottom also increases. Therefore the spring balance reading increases. Thus (a) is correct.

Electrons orbit around the nucleus is correct about them.

The eye can see images separately only if they are exhibited at an interval of more than 1/10 of a second. In the case of a movie, the still pictures come one after the other at less than this minimum interval. So we do not see them separately but only as a continuous moving picture.

The Council of States (Rajya Sabha) is composed of not more than 250 members, of whom 12 are nominated by the President. The twelve members are chosen by him from among persons having special knowledge or practical experience in literature, science, art, and social service. The Constitution thus adopts the principle of nomination, for according distinguished Indians a place in the Upper Chamber (Rajya Sabha) of Parliament.