SSC CGL Previous Year Questions: General Science - 9 - SSC CGL MCQ

Brass is an alloy made of copper and zinc; the proportions of zinc and copper can be varied to create a range of brasses with varying properties.

Wrought iron is an iron alloy with a very low carbon content, in comparison to steel, and has fibrous inclusions, known as slag. This is what gives it a "grain" texture resembling wood, which is visible when it is etched or bent to the point of failure. Wrought iron is tough, malleable, ductile and easily welded.

Galvanization, or galvanisation, is the process of applying a protective zinc coating to steel or iron, to prevent rusting. The most common method is hot-dip galvanization, in which parts are submerged in a bath of molten zinc.

A homogeneous mixture is a type of mixture in which the composition is uniform and every part of the solution has the same properties. A homogeneous mixture in which there is both a solute and solvent present is known as solution.

The plant epidermis consists of three main cell types: pavement cells, guard cells and their subsidiary cells that surround the stomata.

As sugar concentration increases in the guard cells, as a result water enters the guard cells. The guard cells become turgid (swollen with water). The thin outer walls bulge out and force the inner wall into a crescent shape. In this way a stoma or pore is formed between each pair of guard cell.

Mahyco, an Indian seed company based in Jalna, Maharashtra, has developed the Bt brinjal. The genetically modified brinjal event is termed Event EE 1 and Mahyco have also applied for approval of two brinjal hybrids.

Morphine is the most abundant opiate found in opium, the dried latex from unripe seedpods of Papaver somniferum (the opium poppy).

Efforts by the U.S. Soil Conservation Service to promote contouring in the 1930s as an essential part of erosion control eventually leading to its widespread adoption. The practice has been proved to reduce fertilizer loss, power and time consumption, and wear of machines, as well as to increase crop yields and reduce erosion. Contour farming is most effective when used in conjunction with such practices as strip cropping, terracing, and water diversion.

Glucose has the molecular formula C₆H₁₂O₆ and is thus a hexose sugar.

Bacteria are prokaryotes, which, by definition, are cells that don't possess membrane-bound organelles. Mitochondria are membrane-bound organelles.

The rainbow comes from the reflection and refraction of the sunlight in the falling drops; its colors are mainly due to dispersion, which means that the refractive index of water depends on the wavelength of light.

When a ray of light falls on sea shell, then its small amount gets refracted (slightly polarised) and rest almost gets reflected back (fully polarised).

An object covers distance which is directly proportional to the square of the time. Its acceleration is constant.

If the horizontal range of a projectile is four times its maximum height, the angle of projection is 45 degrees. Range is the total horizontal distance covered during the time of flight. It is calculated as  where θ is the angle of projection.

Mercury has the least melting point of the following metals (–38.83°C). Gold, silver and copper have 1064°C, 961.8°C and 1085°C respectively

Marsh Gas or methane gas is produced when vegetation decomposes in water. Methane, also called marsh gas is colourless, odourless gas that occurs abundantly in nature as the chief constituent of natural gas, as a component of fire damp in coal mines, and as a product of the anaerobic bacterial decomposition of vegetable matter under water.

In cactus, spines are modified leaves.

Mycoplasma are the smallest prokaryotic cells yet discovered, can survive without oxygen and are typically about 0.1 μm in diameter.

Biodiversity can be thought of as the genetic library that keeps life going on Earth. Biodiversity, short for biological diversity, is the term used to describe the variety of life found on Earth and all of the natural processes. This includes ecosystem, genetic and cultural diversity, and the connections between these and all species.

Boiling point of water is lower at higher altitudes due to the decreased air pressure. Boiling point of water changes with altitude because atmospheric pressure changes with altitude.

Sodium thiosulphate, also called sodium hyposulphite or "hypo" is used as a photographic fixer in photography

Hydrogen bomb is based on the principle of nuclear fusion. Hydrogen bomb or H-bomb, weapon deriving a large portion of its energy from the nuclear fusion of hydrogen isotopes. The hydrogen bomb functions by the fusion, or joining together, of lighter elements into heavier elements. The end product again weighs less than its components, the difference once more appearing as energy. Because extremely high temperatures are required in order to initiate fusion reactions, the hydrogen bomb is also known as a thermonuclear bomb.

The commonly used safety fuse wire is made up of an alloy of tin and lead. Fuse is a safety device used in any electrical installation, which forms the weakest link between the supply and the load. It is a short length of wire made of lead / tin /alloy of lead and tin/ zinc having a low melting point and low ohmic losses. A fuse wire should always have a high resistance and low melting point. High resistance to heat up soon and low melting point to melt away due to the heat produced by high resistance so that the circuit is not damaged.

When cooled from room temperature liquid water becomes increasingly dense like other substances, but at approximately 4 °C (39 °F), pure water reaches its maximum density. As it is cooled further, it expands to become less dense.

The linear expansion of a solid rod is independent of the time of heat flow. It is directly dependent on the temperature, length of the rod and material of the rod.

X-rays are produced as a result of obstruction of cathode rays with metal.

Aristotle is the father of Biology and Zoology.

The smallest unit of classification is species. The hierarchy of biological classification's major taxonomic ranks is as follows: species< genus< family < order< class< phylum < kingdom < domain.

Aerenchyma refers to spaces or air channels in the leaves, stems and roots of some plants, which allows exchange of gases between the shoot and the root. Aerenchyma is widespread in aquatic and wetland plants which must grow in hypoxic soils.