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- Question 1 of 22
Supersonic jet causes pollution by thinning of:
Most of high-level supersonic aircraft produce harmful pollutant CFCs in the stratosphere. This leads to the thinning of the O3 (ozone) layer.
- Question 2 of 22
Which type of reaction produces the most harmful radiation?
Fission reaction produces the most harmful radiation. In nuclear fission reaction, the nucleus of an atom splits into two or more smaller nuclei. The fission process often produces gamma photons and releases a very large amount of energy even by the energetic standards of radioactive decay.
- Question 3 of 22
Which type of glass is used for making glass reinforced plastic?
Fibreglass is used for making glass-reinforced plastic (GRP). The fibres are usually glass, carbon, aramid, or basalt. Rarely, other fibres such as paper, wood, or asbestos have been used. It is strong, extremely light and highly versatile.
- Question 4 of 22
Glycol is added to aviation gasoline because it:
Ethylene glycol is added to aviation gasoline because it prevents the freezing of petrol. It is an organic compound and has a low freezing point. In the US and Latin countries, the term gasoline is used, but in Europe and Asian countries, it’s called petrol.
- Question 5 of 22
Which of the following gases is used in the yellow lamps used for street lighting?
Sodium is used in the yellow lamps used for street lighting. Sodium-vapour lamps are good for night-time illumination because of their high efficiency and because the light they produce penetrates mist and fog particularly well.
- Question 6 of 22
Lens is made up of:
Flint glass is optical glass that has relatively high refractive index and low Abbe number (high dispersion). For this reason, it is used for making the lens and prism.
- Question 7 of 22
Which of the following is responsible for the extra strength of pyrex glass?
Pyrex is low-thermal-expansion borosilicate glass. It is a type of glass that is resistant to heat, chemicals, and electricity. Borax is used for the extra strength of pyrex glass.
- Question 8 of 22
The temperature of oxyacetylene flame is around:
Oxyacetylene flame is commonly known as gas welding. It is a process which relies on combustion of oxygen and acetylene. When mixed together in correct proportions within a hand-held torch or blowpipe, a relatively hot flame is produced with a temperature of about 3200°C.
- Question 9 of 22
The Refrigerant ‘FREON’ is:
Freon is a non-combustible gas that is used as a refrigerant in air conditioning applications. It is Dichlorodifluoromethane (CCl2F2). Dichlorodifluoromethane is a colorless gas usually sold under the brand name Freon-12.
- Question 10 of 22
A balloon filled with helium rises in the air because:
A balloon filled with helium rises in the air because helium is less dense (lighter) than air. Helium floats because its molecules are lighter than the nitrogen and oxygen molecules of our atmosphere and so they rise above it.
- Question 11 of 22
Cooking oil is converted into vegetable ghee by the process of:
Cooking oil is converted into vegetable ghee by the process of Hydrogenation. Hydrogenation is a process where manufacturers add hydrogen to cooking oil, to turn it into a solid fat at room temperature.
- Question 12 of 22
Which of the toxic heavy metals is found in modern tannery industries?
- Question 13 of 22
Which of the following contains high content of lead?
High octane fuel contains high content of lead. If tetraethyl lead, Pb(CH2CH3)4, was put into petrol, particles of lead and lead oxide PbO are formed on combustion. This helps the petrol to burn more slowly and smoothly, preventing knocking and giving higher Octane ratings.
- Question 14 of 22
Stainless steel is an alloy of:
Stainless steel is an alloy of chromium, carbon and iron. It contains 10 to 30 percent chromium, less than 1.2% carbon and other alloying elements.
- Question 15 of 22
Raw materials used for the manufacture of glass are:
The raw materials used for the manufacture of glass are 71 percent silica (sand), 14 percent soda ash (sodium carbonate), 11 percent limestone (calcium) and 4 percent other ingredients. These raw materials are melted at very high temperature to form a new material ‘glass’.
- Question 16 of 22
Which of the following is used in welding broken pieces of iron rails and machine parts?
The reduction of a metal oxide to form metal by using aluminium powder as a reducing agent is called a thermite reaction. It is an exothermic reaction in which a large amount of heat is evolved. This reduction property of aluminium is used in welding broken pieces of iron rails and machine parts.
- Question 17 of 22
The BOD values of water indicate the:
Biological oxygen demand (BOD) generally represents how much oxygen is needed to break down organic matter in water. Clean water has BOD which is less than 5 ppm.
- Question 18 of 22
The product used for manufacturing of Industrial alcohol is:
The product used for manufacturing of Industrial alcohol is Molasses. Ethanol is the major product obtained from molasses by means of anaerobic fermentation using microorganisms.
- Question 19 of 22
The metals commonly used for electroplating are:
Electroplating is the process of coating a metal with a thin layer of another metal by electrolysis to improve the metal’s corrosion resistance. The metals commonly used for electroplating are nickel, chromium, cadmium, copper, gold, palladium, platinum, ruthenium, silver, tin and zinc.
- Question 20 of 22
Which of the following in automobile exhaust can cause cancer?
Excessive exposure to polycyclic aromatic hydrocarbons (PAHs) often results in lung cancer.
- Question 21 of 22
Cement is usually a mixture of:
Cement is usually a mixture of calcium silicate and calcium aluminate. cement is a powdery substance made with calcined lime and clay as major ingredients. The clay used provides silica, alumina, and iron oxide, while calcined lime basically provides calcium oxide.
- Question 22 of 22
Electric bulbs are filled with:
Electric bulbs are filled with Argon. The heat from the tungsten filament generates light and the argon helps prevent the filament from decaying.