General Physical Science

 In the industrial production of vegetable ghee, the process involved is reduction.

An emulsion is a mixture of two or more liquids that are normally immiscible. In an emulsion, one liquid (the dispersed phase) is dispersed in the other (the continuous phase). Examples of emulsions include milk, mayonnaise etc.

Cinnaba or cinnabarite (red mercury(II) sulfide (HgS), native vermilion), is the common ore of mercury.

To breathe underwater a diver must be supplied air at a pressure equal to that of the water surrounding the diver. Air of course is a suitable breathing mixture for a diver based primarily on nitrogen as the oxygen diluent. Beyond this depth helium is preferred as the diluent and is in fact particularly well suited to the depth. Helium does not cause narcosis at these pressures, is relatively inexpensive and is readily available.

Tetraethyl lead (TEL) is extensively used as an additive to gasoline, wherein it served as an effective antiknock agent and prevented exhaust valve and seatwear.

Because it is a solid material, it is known as a dry lubricant. Graphite is the only non-metal element that is a good conductor of electricity.

Sodium nitrate is the chemical compound. Sodium nitrate is used as a constituent of fertilizers.

Hydrogen is the lightest element and makes up most of the universe (about 90% of the universe is made of hydrogen).

The diesel engine has proved to be extremely efficient and cost effective. Diesel engines in automobiles provide higher mileage, making it an obvious choice for heavy-duty transportation and equipment. And diesel engines are attracting greater attention due to higher efficiency and cost effectiveness.

The element present in the largest amount in rocks and minerals is silicon.

Alkaloid - one of a large group of organic, basic substances found in plants. They are usually bitter in taste and are characterized by powerful physiologic activity. Examples are morphine, cocaine, atropine, quinine, nicotine, and caffeine. The term is also applied to synthetic substances that have structures similar to plant alkaloids, such as procaine.

 This is to prevent microbial growth.

Diamond is made up of pure carbon. In the structure of diamond, one carbon atom is attached to four other carbon atoms forming covalent bonds. All the electrons of each carbon atom are shared and the octet rule is satisfied. Hence, no free electron is left for the conduction of electricity.

Diamond and emerald are made of carbon and beryllium respectively.

 The atomic weight of hydrogen is approximately the same as its atomic number.

Their attenuation is dependent upon the density of the shielding material; it can be shown that a dense shield material with a higher atomic number is a better attenuator of X-rays. Lead enjoys the advantage of being the densest of any commonly available material. Where space is at a premium and radiation protection is important, lead is often preferred. It is recognised that lead is not the densest element (e.g. tantalum, tungsten and thorium are higher on the density scale), but lead is readily available, easily fabricated and the cheapest of these materials.

Earth’s crust is the major source of metals.

 Ozone is heavier than oxygen.

 Swelling of a sprained foot is reduced by soaking in hot water containing a large amount of common salt. This is because of a phenomenon called plasmolysis.

 The powder used for developing finger prints on a multicoloured surface is fluorescent powder.

There is rapid increase of pressure in confined space in case of explosion.

Both statements are correct.